JP7097064B2 - Pseudo-progressive wave resonator and antenna device - Google Patents

Description

The present invention relates to a pseudo traveling wave resonator and an antenna device using a non-reciprocal phase shift right-handed / left-handed composite transmission line.

Recently, much research has been conducted on right-handed / left-handed composite transmission lines (hereinafter referred to as "non-reciprocal transmission lines") made of metamaterials that cause non-reciprocal phase shifts in the forward and reverse directions. The non-reciprocal transmission line can operate as a kind of transmission line resonator in which the size of the resonator and / or the phase distribution gradient on the resonator can be freely changed without changing the resonance frequency. Also called a "pseudo-travel wave resonator".

For example, Patent Documents 1 and 2 disclose an antenna device in which a non-reciprocal transmission line is formed in a loop shape and power is supplied to the loop-shaped non-reciprocal transmission line to generate circularly polarized waves.

Japanese Unexamined Patent Publication No. 2016-0544454 Japanese Unexamined Patent Publication No. 2017-152981

Conventionally, a pseudo traveling wave resonator and an antenna device provided with a loop-shaped non-reciprocal transmission line have a narrow band, and are required to operate in a wider band.

An object of the present invention is to provide a pseudo traveling wave resonator and an antenna device provided with a loop-shaped non-reciprocal transmission line, which can operate in a wider band than before. ..

According to the first aspect of the present invention.
A quasi-traveling wave resonator with a non-reciprocal transmission line containing multiple unit cells interconnected along a loop.
Each of the plurality of unit cells equivalently includes a microwave transmission line portion, a series branch circuit including a capacitive element equivalently, and an inductive element provided by branching from the transmission line portion. Equipped with a parallel branch circuit,
The transmission line portion of each unit cell is magnetized in a different direction with respect to the propagation direction of the microwave and has spontaneous magnetization so as to have gyro anisotropy, or is magnetized by an external magnetic field.
In the pseudo traveling wave resonator, the reflection loss of the pseudo traveling wave resonator is equal to or less than a predetermined threshold value in the frequency band from the frequency of the +1st order resonance or the frequency of the -1st order resonance to the frequency of the 0th order resonance. Has a frequency of +1 or -1st resonance determined by
The pseudo-progressive wave resonator has a forward phase constant β ₊ and a reverse phase constant β corresponding to the determined +1 or -1st-order resonance frequencies in the dispersion curve of the pseudo-progressive wave resonator. _-Has
The number M of the unit cells is determined so that + N / (2M) or −N / (2M) has the value closest to β _B / β _A.
here,
N indicates a value obtained by dividing the circumference of the loop by the length of each unit cell of the non-reciprocal transmission line.
β _A indicates (β ₊ + β- ₎ / 2,
β _B indicates (β _{+ -β-} ) / 2.

According to the second aspect of the present invention, in the first aspect,
The pseudo traveling wave resonator has such that the reflection loss of the pseudo traveling wave resonator is equal to or less than the predetermined threshold value in the frequency band from the frequency of the -1st order resonance to the frequency of the +1st order resonance. It has the determined frequency of the +1st order resonance and the frequency of the -1st order resonance.
The pseudo traveling wave resonator has a forward phase constant β _{+ (+1)} and a reverse phase constant β _{− (} corresponding to the determined +1st order resonance frequency in the dispersion curve of the pseudo traveling wave resonator. It has ₊₁₎ and a forward phase constant β _{+ (-1)} and a reverse phase constant β _{− (-1)} corresponding to the determined frequency of the first-order resonance.
As for the number M of the unit cells, one of + N / (2M) and −N / (2M) has a value closest to β _{B (+1)} / β _{A (+1)} , and + N / (2M) and The other of -N / (2M) was determined to have the closest value to β _{B (-1)} / β _{A (-1)} .
here,
β _{A (+1)} indicates (β _{+ (} +1) + β- (+1 ₎ ) / 2,
β _{B (+1)} indicates (β _{+ (} +1) -β- (+1 ₎ ) / 2,
β _{A (-1)} indicates (β ₊ (-1) + β- (-1 ₎ ) / 2,
β _{B (-1)} indicates (β ₊ (-1) -β- (-1 ₎ ) / 2.

According to the third aspect of the present invention, in the first or second aspect,
The circuit of the parallel branch is an inductive stub circuit connected to the inner circumference of the loop-shaped non-reciprocal transmission line.

According to the fourth aspect of the present invention.
An antenna device including a pseudo-progressive wave resonator according to one of the first to third aspects is provided.

According to one aspect of the present invention, there is provided a pseudo traveling wave resonator and an antenna device provided with a loop-shaped non-reciprocal transmission line, which can operate in a wider band than the conventional one. be able to.

It is a top view which shows the structure of the antenna device provided with the pseudo-progressive wave resonator 1 which concerns on embodiment. It is sectional drawing of the unit cell 21-1 in the AA' line of FIG. It is a circuit diagram which shows the equivalent circuit of the unit cell 21-m when the pseudo traveling wave resonator 1 of FIG. 1 operates as a reciprocal phase shift right-handed / left-handed composite transmission line. It is a circuit diagram which shows the equivalent circuit of the unit cell 21-m when the pseudo traveling wave resonator 1 of FIG. 1 operates as a non-reciprocal transmission line. It is a figure which shows the dispersion curve for demonstrating the +1st order resonance, the 0th order resonance, and the -1st order resonance of the pseudo-progressive wave resonator 1 of FIG. It is a figure which shows the frequency characteristic of the reflection loss for demonstrating the operation band of the pseudo-progressive wave resonator 1 of FIG. It is a graph which shows the dispersion curve when the positive magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. It is a graph which shows the dispersion curve when a negative magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. It is a graph which shows the frequency characteristic of the reflection loss when a positive magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. It is a graph which shows the frequency characteristic of the reflection loss when a negative magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. It is a graph which shows the frequency characteristic of the radiation gain when a positive magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. It is a graph which shows the frequency characteristic of the axial ratio when a positive magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. It is a graph which shows the frequency characteristic of the radiation gain when a negative magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. It is a graph which shows the frequency characteristic of the axial ratio when a negative magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. 3 is a graph of simulation results showing directivity at an operating frequency of 5.22 GHz when positive spontaneous magnetization is applied to the pseudo-progressive wave resonator 1 of FIG. 1. It is a graph of the simulation result which shows the directivity at the operating frequency of 5.48GHz when the positive spontaneous magnetization is applied to the pseudo-progressive wave resonator 1 of FIG. 6 is a graph of actual measurement results showing directivity at an operating frequency of 5.46 GHz when a positive external magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. 1. 6 is a graph of actual measurement results showing directivity at an operating frequency of 5.59 GHz when a positive external magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. 1. It is a graph of the simulation result which shows the directivity at the operating frequency 5.22GHz when the negative spontaneous magnetization is applied to the pseudo-progressive wave resonator 1 of FIG. It is a graph of the simulation result which shows the directivity at the operating frequency of 5.48GHz when the negative spontaneous magnetization is applied to the pseudo-progressive wave resonator 1 of FIG. 6 is a graph of actual measurement results showing directivity at an operating frequency of 5.40 GHz when a negative external magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. 1. 6 is a graph of actual measurement results showing directivity at an operating frequency of 5.58 GHz when a negative external magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. 1.

Hereinafter, the pseudo-progressive wave resonator and the antenna device according to the embodiment of the present invention will be described with reference to the drawings. In each drawing, the same reference numerals indicate similar components.

FIG. 1 is a plan view showing the configuration of an antenna device including the pseudo-progressive wave resonator 1 according to the embodiment. FIG. 2 is a cross-sectional view of the unit cell 21-1 on the AA'line of FIG. The pseudo-progressive wave resonator 1 includes a non-reciprocal transmission line 20 including a plurality of unit cells 21-1 to 21-M (hereinafter, also referred to as “unit cell 21”) longitudinally connected along a loop in the forward direction. It results in non-reciprocal phase shifts in the opposite direction (eg counterclockwise) (eg clockwise).

The pseudo-progressive wave resonator 1 includes a flat dielectric substrate 10 and a magnetic ring 11 embedded in the dielectric substrate 10. The magnetic ring 11 is made of, for example, ferrite. The magnetic ring 11 has a radius R0 to its center line, a radius R1 on the outer circumference, and a width w1. Further, as shown in FIG. 2, a ground conductor 12 is formed on the lower surfaces of the dielectric substrate 10 and the magnetic ring 11.

Each unit cell 21 is provided along the center line of the magnetic ring 11 with a period of length p. Each unit cell 21 has a width w1. The length p is, for example, the length of the circumference along the center line of the magnetic ring 11 (that is, the length of the circumference of the loop of the non-reciprocal transmission line 20) 2π · R0, which is a predetermined integer N (N). > Has a value divided by M). However, the length 2π · R0 of the circumference along the center line of the magnetic ring 11 generally does not need to be an integral multiple of the length p of the unit cell. Therefore, the number N (N> M) does not have to be an integer value, and is defined as a real value obtained by dividing the circumference length 2π · R0 along the center line of the magnetic material ring 11 by the unit cell length p. ..

Each unit cell 21 includes strip conductors 13, 14, via conductors 15, and a capacitor Cp. The strip conductor 13 is formed on the magnetic ring 11 and together with the ground conductor 12 forms a microstrip line (ie, a microwave transmission line portion). The microwave propagates along the magnetic ring 11. Capacitors Cp are connected between strip conductors 13 of unit cells 21 adjacent to each other. The strip conductor 14 is formed on the dielectric substrate 10 inside the magnetic ring 11 and is connected to the strip conductor 13. The via conductor 15 is formed so as to penetrate the dielectric substrate 10 so as to connect the tip of the strip conductor 14 and the ground conductor 12 to each other. As described above, each unit cell 21 is provided with a microwave transmission line portion, a series branch circuit (capacitor Cp) equivalently including a capacitive element, and an inductive element branched from the transmission line portion. It is provided with a circuit of parallel branches (strip conductor 14 and via conductor 15) including equivalently. The circuit of the parallel branch is an inductive stub circuit connected to the inner circumference of the loop-shaped non-reciprocal transmission line 20.

The transmission line portion of each unit cell 21 is magnetized in a different direction with respect to the propagation direction of the microwave and has spontaneous magnetization so as to have gyro anisotropy, or is magnetized by an external magnetic field. The magnetic ring 11 may have spontaneous magnetization in, for example, the + Z direction or the −Z direction. Alternatively or additionally, the magnetic ring 11 may be magnetized, for example, in the + Z direction or the −Z direction by an external magnetic field such as an electromagnet 50, as shown in FIG. In the present specification, the magnetic field in the + Z direction is defined as a positive magnetic field.

The pseudo-progressive wave resonator 1 may have a region (that is, a region having no strip conductors 13 and 14, a via conductor 15, and a capacitor Cp) that does not form a unit cell 21 in a part of the magnetic ring 11. good. In FIG. 1, such an area is shown as virtual cells 22- (M + 1) to 30-N (hereinafter, also referred to as "virtual cell 22"). The dimensions of each virtual cell 22 are the same as the dimensions of each unit cell 21 and have a period of length p.

The reflection element 16 is connected to the unit cell 21-1 at one end of the non-reciprocal transmission line 20 via the capacitor C1, and to the unit cell 21-M at the other end of the non-reciprocal transmission line 20 via the capacitor C2. The reflective element 17 is connected. Each of the reflecting elements 16 and 17 is made of a strip conductor. By connecting the reflecting elements 16 and 17 to both ends of the non-reciprocal transmission line 20, both ends become short-circuited ends. The tips of the reflecting elements 16 and 17 are referred to as ports P11 and P12, respectively. In the example of FIG. 1, a 50Ω feeding line 18 made of a strip conductor is connected to the port P11. The feeding line 18 is further connected to the wireless communication circuit 2, whereby the pseudo-progressive wave resonator 1 operates as an antenna device.

Next, the operating principle of the non-reciprocal transmission line 20 will be described with reference to FIGS. 3 and 4.

FIG. 3 is a circuit diagram showing an equivalent circuit of a unit cell 21-m when the pseudo traveling wave resonator 1 of FIG. 1 operates as a reciprocal phase shift right-handed / left-handed composite transmission line. 3 shows the case where the magnetic ring 11 of FIGS. 1 and 2 does not have spontaneous magnetization and magnetization due to an external magnetic field, so that the electric power propagates in the forward direction (rightward) and in the reverse direction (leftward). The case of propagating and the case of having the same propagation constant are shown.

In FIG. 3, the unit cell 21-m is provided with a period of length p, a port P1 composed of terminals T1 and T2 is provided at one end thereof, and a port P2 composed of terminals T3 and T4 is provided at the other end. .. The unit cell 21-m is
(1) Impedance Zse of a series branch composed of a series resonant circuit of capacitance CL and inductance _{L R} ,
(2) It has an admittance Ysh of a parallel branch composed of a parallel resonant circuit having a capacitance _CR and an inductance L _L.

Here, the series resonance frequency and the parallel resonance frequency of the unit cell 21-m are determined by the impedance Zse of the series branch and the admittance Ysh of the parallel branch, respectively. The capacitance CL inserted in series and the inductance _{L L inserted} in parallel realize negative magnetic permeability and negative permittivity, respectively.

FIG. 4 is a circuit diagram showing an equivalent circuit of the unit cell 21-m when the pseudo traveling wave resonator 1 of FIG. 1 operates as a non-reciprocal transmission line. In FIG. 4, unlike the case of FIG. 3, the magnetic material ring 11 has spontaneous magnetization or magnetization due to an external magnetic field, and the electric power propagates in the forward direction (rightward) and the electric power propagates in the reverse direction (leftward). In some cases, the propagation constants are different from each other, and in particular, non-reciprocal transfers having different phase constants from each other are shown.

In the example of FIG. 4, it is assumed that the strip conductor 14 having the admittance Y of the parallel branch and the via conductor 15 are connected to the center of the strip conductor 13 (shown as two equally divided strip conductors 12a) of FIG. .. Since each capacitor Cp in FIG. 1 is shared between adjacent unit cells 21, it is shown in FIG. 4 that the unit cell 21-m comprises two capacitors having a capacitance Cp / 2. When operating as a non-reciprocal transmission line, the pseudo-progressive wave resonator 1 has a forward impedance Z ₊ and a forward phase constant β ₊ , and a reverse impedance Z ₋ and a reverse phase constant β ₋ . ..

Non-reciprocity is manifested by connecting strip conductors 14 and via conductors 15, which have admittance Y of parallel branches, asymmetrically with respect to the transmission line portion.

Next, the operating principle of the pseudo-progressive wave resonator 1 according to the embodiment will be described with reference to FIGS. 5 and 6.

FIG. 5 is a diagram showing a dispersion curve for explaining the +1st order resonance, the 0th order resonance, and the -1st order resonance of the pseudo-progressive wave resonator 1 of FIG.

In the following description, the following phase characteristic values β _A and β _B based on the forward phase constant β ₊ and the reverse phase constant β ₋ are used.

β _A = (β ₊ + β- ₎ / 2 (1)
β _B = (β _{+ -β-} ) / 2 (2)

When the forward phase constant β ₊ and the reverse phase constant β ₋ are equal to each other (β _B = 0), the pseudo-progressive wave resonator 1 operates as a 0th-order resonator. In contrast to conventional resonators (half-wavelength resonators, one-wavelength resonators, etc.) whose electromagnetic field distribution has antinodes and nodes, the 0th-order resonator has a uniform electromagnetic field distribution and current distribution everywhere. The 0th-order resonator can be composed of a non-reciprocal transmission line 20 and a pair of reflecting elements 16 and 17 connected to both ends thereof. The resonance circuit of the series branch and the resonance circuit of the parallel branch included in each unit cell 21 selectively operate depending on the conditions (short circuit or open) realized by the reflecting elements 16 and 17 at both ends. When the reflecting elements 16 and 17 at both ends have an impedance of 0 (meaning a short-circuited end), the resonant circuit of the series branch of each unit cell 21 operates selectively. At this time, the impedance Z of the series branch of each unit cell 21 is almost all 0. As a result, a large current having a uniform size and phase flows through the series branches of each unit cell 21. That is, it is the 0th-order resonance in the case of a short circuit at both ends. On the other hand, when the impedances of the reflecting elements 16 and 17 at both ends are infinite (meaning the open end), the resonant circuit of the parallel branch of each unit cell 21 operates selectively. At this time, the admittance Y of the parallel branches of each unit cell 21 is almost all 0. As a result, a voltage having a uniform size and phase is applied to both ends of the parallel branch of each unit cell 21. That is, it is the 0th-order resonance when both ends are open. In the case of 0th order resonance, an electromagnetic field distribution having a uniform amplitude and phase is obtained along the non-reciprocal transmission line 20.

In the dispersion curve of FIG. 5, at the frequency f ₀ , the forward phase constant β ₊ and the reverse phase constant β ₋ are equal to each other, so that the pseudo-progressive wave resonator 1 operates as a 0th-order resonator.

When the amount of phase shift when the microwave propagates over the entire non-reciprocal transmission line 20 becomes 2π, the pseudo traveling wave resonator 1 operates as a +1st order resonator. Since the phase gradient of the non-reciprocal transmission line 20 depends on the phase characteristic value β _B , the condition of the +1st order resonance is given by the following equation.

2β _B・ M ・ p = + 2π (3)

Here, M indicates the number of unit cells 21, and p indicates the length of the unit cells 21.

In the dispersion curve of FIG. 5, it is assumed that the pseudo-progressive wave resonator 1 has a phase characteristic value β _B satisfying the equation (3) at a frequency f ₊ 1 and therefore operates as a +1 order resonator.

When the amount of phase shift when the microwave propagates over the entire non-reciprocal transmission line 20 becomes -2π, the pseudo traveling wave resonator 1 operates as a -1st order resonator. The condition of -1st resonance is given by the following equation.

2β _B・ M ・ p = -2π (4)

In the dispersion curve of FIG. 5, it is assumed that the pseudo-progressive wave resonator 1 has the phase characteristic value β _B satisfying the equation (4) at the frequency f _-1 , and therefore operates as a -1st order resonator.

Further, the pseudo-progressive wave resonator 1 operates as an antenna device that generates circular polarization when the following conditions are satisfied.

β _A・ N ・ p = 2π (5)

Here, N indicates a value obtained by dividing the circumference length 2π · R0 of the loop of the non-reciprocal transmission line 20 by the length p of each unit cell 21.

However, in the case of the loop-shaped non-reciprocal transmission line 20, circular polarization can be generated if the phase difference between the orthogonal elements is 90 degrees. Therefore, the radiation of circularly polarized waves does not depend on the number M of unit cells, but depends on the phase gradient in the loop-shaped non-reciprocal transmission line 20, that is, the magnitude of non-reciprocity.

The following equations can be obtained from the equations (3) and (5).

β _B / β _A = + N / (2M) (6)

When the equation (6) is satisfied, the pseudo-progressive wave resonator 1 operates as an antenna device that satisfies the condition of +1st order resonance and generates circular polarization.

Further, the following equations can be obtained from the equations (4) and (5).

β _B / β _A = -N / (2M) (7)

When the equation (7) is satisfied, the pseudo-progressive wave resonator 1 operates as an antenna device that satisfies the condition of -1st order resonance and generates circular polarization.

FIG. 6 is a diagram showing the frequency characteristics of the reflection loss for explaining the operating band of the pseudo-progressive wave resonator 1 of FIG.

When the pseudo-progressive wave resonator 1 operates as a -1st order resonator, it has a center frequency f _-1 and a 3 dB bandwidth B _-1 in the operating band. Further, when the pseudo-progressive wave resonator 1 operates as a 0th-order resonator, it has a center frequency f ₀ and a 3 dB bandwidth B ₀ of the operating band. Further, when the pseudo-progressive wave resonator 1 operates as a +1st-order resonator, it has a center frequency f _{+ 1} and a 3 dB bandwidth B ₊ 1 in the operating band.

As shown in FIG. 6, when the quasi-traveling wave resonator 1 operates as one of a +1st order resonator, a 0th order resonator, and a -1st order resonator, the operating band is narrow and is separated from the central frequency of the operating band. As the reflection loss increases. In the frequency band from -1st resonance frequency f _-1 to 0th resonance frequency f ₀ , the reflection loss exceeds -3dB at the intermediate frequency, and the 0th resonance frequency f ₀ to +1th resonance. Of the frequency band up to the frequency f _{+ 1} , the reflection loss exceeds -3 dB at the intermediate frequency.

Considering the frequency characteristics of FIG. 6, if the frequency f _-1 of the -1st resonance is sufficiently close to the frequency f ₀ of the 0th resonance, the reflection loss becomes -3dB or less at the intermediate frequency, and the -1st order. It is considered that the pseudo traveling wave resonator 1 can be operated over a frequency band from the resonance frequency f _-1 to the _0th -order resonance frequency f0. Therefore, the frequency f-1 of the _-1st resonance is determined so as to satisfy the following equation.

f ₀ -B _0/2 <f _-1 + B _-1 / 2 (8)

Similarly, if the frequency f ₊₁ of the +1st resonance is sufficiently close to the frequency f ₀ of the 0th resonance, the reflection loss becomes -3dB or less at the intermediate frequency, and the frequency f ₊₁ of the +1th resonance to the 0th resonance. It is considered that the pseudo traveling wave resonator 1 can be operated over the frequency band up to the frequency f ₀ of. Therefore, the frequency f ₊ 1 of the +1st-order resonance is determined so as to satisfy the following equation.

f ₊₁ -B _+1/2 <f ₀ + B _0/2 (9)

The conditions of the equations (8) and (9) may be expressed as the following equations using the Q value.

Here, Q _-1 = f _-1 / B _-1 , Q ₀ = f ₀ / B ₀ , Q ₊₁ = f ₊₁ / B ₊₁ .

By determining the frequency f _-1 of the -1st order resonance so as to satisfy the equation (8) or the equation (10), and / or the frequency of the +1st order resonance so as to satisfy the equation (8) or the equation (10). By determining f _{+ 1} , the pseudo-progressive wave resonator 1 can operate in a wider band than before.

The pseudo-progressive wave resonator 1 according to the embodiment is configured as follows.

The +1th-order resonance frequency f _-1 and the -1st-order resonance frequency f ₊₁ of the quasi-traveling wave resonator 1 quasi-progress in the frequency band from the -1st-order resonance frequency f _-1 to the +1st-order resonance frequency f ₊₁ . The reflection loss of the wave resonator 1 is determined to be equal to or less than a predetermined threshold value (for example, -3 dB).

Next, as shown in FIG. 5, in the dispersion curve of the pseudo traveling wave resonator 1, the forward phase constant β _{+ (+1)} and the reverse phase constant β ₋ corresponding to the determined +1 order resonance frequency. ₍₊₁₎ and the forward phase constant β _{+ (-1)} and the reverse phase constant β _{− (} -1) corresponding to the determined frequency of the first-order resonance are determined.

Next, the number M of the unit cells 21 has a value in which one of + N / (2M) and −N / (2M) is closest to β _{B (+1)} / β _{A (+1)} , and + N / ( The other of 2M) and −N / (2M) is determined to have the closest value to β _{B (-1)} / β _{A (-1)} .

Here, the following phase characteristic values β _{A (+1)} , β _{B (+1)} , β _{A (-1)} , and β _{B (-1)} are used.

β _{A (+1)} = (β _{+ (} +1) + β- (+1 ₎ ) / 2 (12)
β _{B (+1)} = (β _{+ (} +1) -β- (+1 ₎ ) / 2 (13)
β _{A (-1)} = (β ₊ (-1) + β- (-1 ₎ ) / 2 (14)
β _{B (-1)} = (β ₊ (-1) -β- (-1 ₎ ) / 2 (15)

In the ideal case, the following equations (16) and (17) hold, or the equations (18) and (19) hold.

β _{B (+1)} / β _{A (+1)} = + N / (2M) (16)
β _{B (-1)} / β _{A (-1)} = -N / (2M) (17)

β _{B (+1)} / β _{A (+1)} = -N / (2M) (18)
β _{B (-1)} / β _{A (-1)} = + N / (2M) (19)

As a matter of course, since the number M of unit cells is an integer value, the equal signs of equations (16) to (19) do not always hold. However, the equal number is substantially established, that is, by determining the number M of the unit cells 21 so as to minimize the error, the frequency f _-1 of the -1st-order resonance to the frequency f ₊₁ of the +1st-order resonance. The pseudo traveling wave resonator 1 can be operated as an antenna device that keeps the reflection loss below the threshold value and generates circular polarization in the frequency band.

The operating band of the quasi-progressive wave resonator 1 is not limited to setting the reflection loss below the threshold value in the frequency band from the frequency f of the _-1st order resonance to the frequency f ₊₁ of the +1st order resonance. As an alternative, the reflection loss of the pseudo traveling wave resonator 1 is set below the threshold value in the frequency band from one of the frequency f ₊₁ of the +1-order resonance and the frequency f _-1 of the -1st-order resonance to the frequency f ₀ of the 0th-order resonance. As such, the frequency f ₊₁ of the +1st order resonance or the frequency f _-1 of the -1st order resonance may be set. In this case, next, in the dispersion curve of the pseudo-progressive wave resonator 1, the forward phase constant β ₊ and the reverse direction corresponding to the determined +1st order resonance frequency f ₊₁ or -1st order resonance frequency f _-1 . Phase constant β ₋ is determined. The number M of unit cells is determined so that + N / (2M) or −N / (2M) has the value closest to β _B / β _A. In this case as well, the reflection loss is set to be equal to or less than the threshold value in the frequency band from one of the frequency f ₊₁ of the +1st resonance and the frequency f _-1 of the -1st resonance to the frequency f ₀ of the 0th resonance, and the circle bias is applied. The pseudo traveling wave resonator 1 can be operated as an antenna device that generates a wave.

Conventionally, a non-reciprocal transmission line having an operating band that can be adjusted depending on the number of unit cells has not been known. According to the pseudo traveling wave resonator 1 according to the embodiment, the frequency f of the +1st order resonance f _{+ 1} and the frequency f _-1 of the -1st order resonance are determined by determining the number M of the unit cells 21 so as to satisfy the above conditions. In the frequency band from at least one of the above to the frequency _f0 of the 0th-order resonance, the reflection loss of the pseudo traveling wave resonator 1 can be set to the threshold value or less, and a wider band operation than in the conventional case can be realized. At the same time, by determining the number M of the unit cells 21 so as to satisfy the above conditions, the pseudo traveling wave resonator 1 can be operated as an antenna device that generates circular polarization.

In general, non-reciprocal transmission lines are formed, for example, by periodically adding a plurality of stub conductors to a microstrip line. However, depending on the position of the stub conductor, the non-reciprocity of the non-reciprocal transmission line may be reduced, and the size of the non-reciprocal transmission line may be increased. The pseudo traveling wave resonator 1 according to the embodiment does not impair the non-reciprocity by connecting the parallel branch circuit (strip conductor 14 and via conductor 15) to the inner circumference of the loop-shaped non-reciprocal transmission line 20. Moreover, a small size can be realized. Structural asymmetry is enhanced by using a combination of the curvature of the looped non-reciprocal transmission line 20 and the asymmetric insertion of the inductive stub circuit.

The antenna device provided with the pseudo traveling wave resonator 1 according to the embodiment can convert the electric power of the incident wave and the electric power of the reflected wave in the non-reciprocal transmission line 20 into a radiated wave. Further, such an antenna device can switch the rotation direction of circular polarization by inverting a DC magnetic field applied from the outside to the non-reciprocal transmission line 20 by using an external magnetic field such as an electromagnet 50. ..

As described above, the pseudo-progressive wave resonator 1 according to the embodiment may have a region in a part of the magnetic ring 11 that does not form the unit cell 21. The number M of the unit cells 21 is determined so as to satisfy the above conditions. The pseudo-progressive wave resonator 1 can operate as long as it has a sufficient number of unit cells 21 to make at least half a circumference of the magnetic ring 11.

The magnetic ring 11 and the non-reciprocal transmission line 20 are not limited to a circular shape, and may have any loop shape as long as they generate circular polarization.

Next, with reference to FIGS. 7 to 14, the simulation results of the frequency characteristics of the pseudo-progressive wave resonator according to the embodiment will be described.

In the simulation, the following parameters were set.

Number of unit cells 21: M = 13
Number of virtual cells 22: 1 (ie, N = 14)
Radius of the center line of the magnetic ring 11: R0 = 8 mm
Radius of the outer circumference of the magnetic ring 11: R1 = 10 mm
Width of magnetic ring 11 and each unit cell 21: w1 = 4 mm
Length (cycle) of each unit cell 21: p = 3.5 mm
Thickness of the dielectric substrate 10 inside the magnetic ring 11: t1 = 0.70 mm
Thickness of magnetic ring 11: t2 = 0.85 mm
Length of strip conductor 14: a1 = 0.5 mm
Length of reflecting elements 16 and 17: a2 = 8.6 mm
Capacitor Cp capacity: 0.6pF
Capacitors C1 and C2 capacity: 1.2pF
Dielectric constant of dielectric substrate 10: 2.6
Dielectric constant of magnetic ring 11: 15

FIG. 7 is a graph showing a dispersion curve when a positive magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. FIG. 8 is a graph showing a dispersion curve when a negative magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. In the case of FIG. 7, at the frequency f _-1 = 5.2 GHz of the first-order resonance, β _B / β _A = −0.559. Further, in the case of FIG. 8, at the frequency f _-1 = 5.2 GHz of the first-order resonance, β _B / β _A = −0.558. When M = 13 and N = 14, −N / (2M) ≈-0538. Therefore, by determining the number M = 13 of the unit cells 21, the pseudo-progressive wave resonator 1 satisfies the condition of -1st-order resonance regardless of whether a positive magnetic field or a negative magnetic field is applied. , Operates as an antenna device that produces circular polarization.

FIG. 9 is a graph showing the frequency characteristics of the reflection loss when a positive magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. FIG. 10 is a graph showing the frequency characteristics of the reflection loss when a negative magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. In the case of FIG. 9, the spontaneous magnetization Ms of the magnetic ring 11 generates a positive magnetic field μ0 · Ms = + 145 mT. In the case of FIG. 10, a negative magnetic field μ0 · Ms = -145 mT is generated by the spontaneous magnetization Ms of the magnetic ring 11. According to FIGS. 9 and 10, the reflection loss is set to about -3 dB or less in the frequency band from the frequency f of the _-1st resonance to the frequency f ₀ of the 0th resonance, and the frequency f ₀ to the 0th order resonance is +1. The reflection loss can be reduced to about -3 dB or less in the frequency band up to the resonance frequency f _{+ 1} .

FIG. 11 is a graph showing the frequency characteristics of the radiation gain when a positive magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. FIG. 12 is a graph showing the frequency characteristics of the axial ratio when a positive magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. 11 and 12 show the gain and axial ratio of the radiated wave having a plane of polarization along the azimuth angle φ = 0 degrees as seen from the position of the elevation angle θ = 0 degrees with respect to the pseudo-progressive wave resonator 1. According to FIG. 11, the specific bandwidth of the radiation band was 15.4%. The specific bandwidth is defined by "(fb-fa) / ((fb + fa) / 2) x 100 [%]" when the lowest frequency of the band is fa and the highest frequency is fb, for example, and the center frequency of the band. Indicates the bandwidth for. According to FIG. 12, the specific bandwidth of the band having the axial ratio of 3 dB or less was 12.8%.

FIG. 13 is a graph showing the frequency characteristics of the radiation gain when a negative magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. FIG. 14 is a graph showing the frequency characteristics of the axial ratio when a negative magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. 13 and 14 also show the gain and axial ratio of the radiated wave having a plane of polarization along the azimuth angle φ = 0 degrees as seen from the position of the elevation angle θ = 0 degrees with respect to the pseudo-progressive wave resonator 1. According to FIG. 13, the specific bandwidth of the radiation band was 14.9%. According to FIG. 14, the specific bandwidth of the band having the axial ratio of 3 dB or less was 11.5%.

Since the conventional antenna device equipped with the pseudo traveling wave resonator uses only a single resonance mode (only one of the +1st order resonance, the 0th order resonance, and the -1st order resonance), its operation. The band is very narrow, about 2 to 3%. On the other hand, according to the antenna device provided with the pseudo traveling wave resonator 1 according to the embodiment, from at least one of the frequency f ₊₁ of the +1st order resonance and the frequency f _-1 of the -1st order resonance to the frequency f ₀ of the 0th order resonance. In the frequency band of, the reflection loss of the pseudo traveling wave resonator 1 can be set to the threshold value or less, and a wider band operation than before can be realized.

Next, with reference to FIGS. 15 to 22, the simulation results of the directivity characteristics of the pseudo-progressive wave resonator according to the embodiment will be described.

In the simulation, the following parameters were set.

Number of unit cells 21: M = 19
Number of virtual cells 22: 1 (ie, N = 20)
Radius of the center line of the magnetic ring 11: R0 = 11 mm
Radius of the outer circumference of the magnetic ring 11: R1 = 13 mm
Length (period) of each unit cell 21: p = 3.4 mm

Other parameters are the same as the simulations of FIGS. 7 to 14.

FIG. 15 is a graph of simulation results showing directivity characteristics at an operating frequency of 5.22 GHz when positive spontaneous magnetization is applied to the pseudo-progressive wave resonator 1 of FIG. 1. FIG. 16 is a graph showing directivity at an operating frequency of 5.48 GHz when positive spontaneous magnetization is applied to the pseudo-progressive wave resonator 1 of FIG. 1.
In FIGS. 15 to 22, the solid line shows the directional characteristics of the radiation wave caused by the left-handed microwave propagation in the non-reciprocal transmission line 20, and the broken line shows the radiation caused by the right-handed microwave propagation in the non-reciprocal transmission line 20. The simulation result shows the directional characteristics of the wave. In the case of FIGS. 15 and 16, the spontaneous magnetization Ms of the magnetic ring 11 generates a positive magnetic field μ0 · Ms = + 115 mT. According to FIGS. 15 and 16, it can be seen that the same directivity can be realized both when operating at a frequency of 5.22 GHz and when operating at a frequency of 5.48 GHz.

FIG. 17 is a graph of actual measurement results showing directivity characteristics at an operating frequency of 5.46 GHz when a positive external magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. FIG. 18 is a graph of actual measurement results showing directivity characteristics at an operating frequency of 5.59 GHz when a positive external magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. In the case of FIGS. 17 and 18, the positive magnetic field μ0 · H0 = + 121 mT is generated by the external magnetic field H0 such as the electromagnet 50. According to FIGS. 17 and 18, it can be seen that the same directivity can be realized both when operating at a frequency of 5.46 GHz and when operating at a frequency of 5.59 GHz.

FIG. 19 is a graph of simulation results showing directivity characteristics at an operating frequency of 5.22 GHz when negative spontaneous magnetization is applied to the pseudo-progressive wave resonator 1 of FIG. 1. FIG. 20 is a graph of simulation results showing directivity characteristics at an operating frequency of 5.48 GHz when negative spontaneous magnetization is applied to the pseudo-progressive wave resonator 1 of FIG. 1. In the case of FIGS. 19 and 20, a negative magnetic field μ0 · Ms = -115 mT is generated by the spontaneous magnetization Ms of the magnetic ring 11. According to FIGS. 19 and 20, it can be seen that the same directivity can be realized both when operating at a frequency of 5.22 GHz and when operating at a frequency of 5.48 GHz.

FIG. 21 is a graph of actual measurement results showing directivity characteristics at an operating frequency of 5.40 GHz when a negative external magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. FIG. 22 is a graph of actual measurement results showing directivity characteristics at an operating frequency of 5.58 GHz when a negative external magnetic field is applied to the pseudo-progressive wave resonator 1 of FIG. In the case of FIGS. 21 and 22, a negative magnetic field μ0 · H0 = -127 mT is generated by an external magnetic field H0 such as an electromagnet 50. According to FIGS. 21 and 22, it can be seen that the same directivity can be realized both when operating at a frequency of 5.40 GHz and when operating at a frequency of 5.58 GHz.

According to FIGS. 7 to 22, it can be seen that the same characteristics can be realized both when a positive magnetic field is applied to the pseudo-progressive wave resonator 1 and when a negative magnetic field is applied.

According to the present invention, it is possible to provide a pseudo traveling wave resonator and an antenna device provided with a loop-shaped non-reciprocal transmission line, which can operate in a wider band than before. ..

1 ... Pseudo-progressive wave resonator,
2 ... Wireless communication circuit,
10 ... Dielectric substrate,
11 ... Magnetic ring,
12 ... Ground conductor,
13, 14 ... Strip conductor,
15 ... Via conductor,
16, 17 ... Reflective element,
18 ... Power supply line,
20 ... Non-reciprocal transmission line,
21-1 to 21-M ... Unit cell,
22- (M + 1) -22-N ... Virtual cell,
50 ... Electromagnet,
Cp, C1, C2 ... Capacitor,
P1, P2, P11, P12 ... Port.

Claims (4)

A quasi-traveling wave resonator with a non-reciprocal transmission line containing multiple unit cells interconnected along a loop.
Each of the plurality of unit cells equivalently includes a microwave transmission line portion, a series branch circuit including a capacitive element equivalently, and an inductive element provided by branching from the transmission line portion. Equipped with a parallel branch circuit,
The transmission line portion of each unit cell is magnetized in a different direction with respect to the propagation direction of the microwave and has spontaneous magnetization so as to have gyro anisotropy, or is magnetized by an external magnetic field.
In the pseudo traveling wave resonator, the reflection loss of the pseudo traveling wave resonator is equal to or less than a predetermined threshold value in the frequency band from the frequency of the +1st order resonance or the frequency of the -1st order resonance to the frequency of the 0th order resonance. Has a frequency of +1 or -1st resonance determined by
The pseudo-progressive wave resonator has a forward phase constant β ₊ and a reverse phase constant β corresponding to the determined +1 or -1st-order resonance frequencies in the dispersion curve of the pseudo-progressive wave resonator. _-Has
The number M of the unit cells is determined so that + N / (2M) or −N / (2M) has the value closest to β _B / β _A.
here,
N indicates a value obtained by dividing the circumference of the loop by the length of each unit cell of the non-reciprocal transmission line.
β _A indicates (β ₊ + β- ₎ / 2,
β _B indicates (β _{+ -β-} ) / 2,
Pseudo-progressive wave resonator. The pseudo traveling wave resonator has such that the reflection loss of the pseudo traveling wave resonator is equal to or less than the predetermined threshold value in the frequency band from the frequency of the -1st order resonance to the frequency of the +1st order resonance. It has the determined frequency of the +1st order resonance and the frequency of the -1st order resonance.
The pseudo traveling wave resonator has a forward phase constant β _{+ (+1)} and a reverse phase constant β _{− (} corresponding to the determined +1st order resonance frequency in the dispersion curve of the pseudo traveling wave resonator. It has ₊₁₎ and a forward phase constant β _{+ (-1)} and a reverse phase constant β _{− (-1)} corresponding to the determined frequency of the first-order resonance.
As for the number M of the unit cells, one of + N / (2M) and −N / (2M) has a value closest to β _{B (+1)} / β _{A (+1)} , and + N / (2M) and The other of -N / (2M) was determined to have the closest value to β _{B (-1)} / β _{A (-1)} .
here,
β _{A (+1)} indicates (β _{+ (} +1) + β- (+1 ₎ ) / 2,
β _{B (+1)} indicates (β _{+ (} +1) -β- (+1 ₎ ) / 2,
β _{A (-1)} indicates (β ₊ (-1) + β- (-1 ₎ ) / 2,
β _{B (-1)} indicates (β ₊ (-1) -β- (-1 ₎ ) / 2,
The pseudo-progressive wave resonator according to claim 1. The parallel branch circuit is an inductive stub circuit connected to the inner circumference of the loop-shaped non-reciprocal transmission line.
The pseudo-progressive wave resonator according to claim 1 or 2. The pseudo-progressive wave resonator according to one of claims 1 to 3 is provided.
Antenna device.

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