JPH025041B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a microwave integrated circuit (abbreviated as MIC) used in low-noise amplifiers and low-noise converters of microwave communication equipment, SHF receivers, and the like.

Conventional configuration and its problems When considering the connection between the low-noise converter and the antenna, the general input structure of the low-noise converter is a waveguide input. Therefore, the input structure of the MIC converter is to add a waveguide-stripline converter, which is a line converter between a microstrip line and a waveguide, to the signal input side of the MIC converter. A common method is to use an input structure. However, the dimensions of each circuit (SHF amplifier, frequency mixer, local oscillator, etc.) that makes up the MIC converter, the connection method of each circuit, the configuration of the waveguide-strip line converter, and the waveguide-strip line Depending on the connection method of the line converter and MIC converter, even if sufficient characteristics are obtained for each circuit alone, it may be difficult to connect each circuit.
When assembled as a MIC converter, various characteristics of the MIC converter (input VSWR, noise figure, local leakage, image suppression ratio, conversion gain, etc.)
The characteristics of each circuit are not reflected directly, and there are many cases where insufficient characteristics are obtained as a MIC converter.

Conventionally, these characteristics were not fully considered.
In many cases, the configuration of each circuit, including the shield case of the MIC converter, and the arrangement of the waveguide-stripline converter were determined.

Purpose of the Invention The purpose of the present invention is to improve the inherent characteristics of each circuit constituting a MIC converter when the circuits are interconnected and assembled as a MIC converter having a waveguide input structure. The objective is to provide a MIC in which the inherent characteristics of the circuit are directly reflected in the characteristics of the MIC converter.

Configuration of the Invention In the present invention, a
A MIC converter consisting of an SHF amplifier, a frequency mixer, and a local oscillator is arranged in a shielded case, and a waveguide-stripline converter is connected to the input stripline of the SHF amplifier, and the input stripline and the The connection point with the waveguide-stripline converter is provided at a position approximately λg/2 (λg is the propagation wavelength within the shielding case) from the end wall surface of the shielding case.

DESCRIPTION OF EMBODIMENTS FIGS. 1a and 1b show a plan sectional view and a side sectional view of an embodiment of a MIC converter according to the present invention.
A SHF amplifier 1, a frequency mixer 2, and a local oscillator 3, which are composed of MIC, are formed on one dielectric substrate 4, and the SHF amplifier 1 is connected to a frequency mixer 2, a local oscillator 3 to the frequency mixer 2, and a local oscillator 3 to the frequency mixer 2. They are connected to each other and placed in the same shield case 5. 6 is the input strip line of SHF amplifier 1,
It is formed together with the SHF amplifier 1 on a dielectric substrate 4 (for example, an alumina substrate, a Teflon glass fiber substrate, etc.), and one end of the input strip line 6 is connected to the SHF amplifier 1, and the other end is connected to a conductor post 7. There is. One end of the conductor post 7 projects into the waveguide 8. A line converter from the waveguide 8 to the input strip line 6 is realized by the conductor post 7 . From the connection point A of the conductor post 7 and the input strip line 6 to the end wall surface B-B' of the shield case 5 (the wall surface of the shield case 5 that is farthest from the local oscillator 3 and closest to the SHF amplifier 1) The position of the conductor post 7 is selected so that the distance l to the shield case 5 is approximately half (lλg/2) of the propagation wavelength λg of the input signal or local oscillation signal in the shield case 5. Here, the propagation wavelength λg within the shield case 5 refers to the wavelength at which the signal propagates on the strip line 6 formed on the dielectric substrate 4, or the wavelength at which the signal propagates directly within the shield case 5. To tell.

In the embodiment shown in FIG. 1, the position of the conductor post 7 is
By selecting λg/2, the connection point A between the input strip line 6 and the conductor post 7 becomes an equivalent short-circuit surface for the waveguide mode propagating inside the shield case 5, and the connection point A The electric field strength of the waveguide mode becomes zero, and it is possible to prevent the input strip line 6 from coupling with the propagation mode in the shield case 5 at the connection point A, which is a discontinuous point of the input strip line 6, and the input strip line Due to the connection point A present at 6, coupling between the SHF amplifier 1 and the propagation mode in the shielding case 5 occurs,
It is possible to prevent the input impedance of the SHF amplifier 1 from becoming unstable. In other words, shield case 5
The state in which it is covered and the state in which it has been removed.
Changes in the input impedance of the SHF amplifier 1 are extremely small. Therefore, the input impedance of the SHF amplifier 1 can be designed without covering the shield case 5.
design becomes easier. At the same time, it has the effect of reducing unnecessary radiation leakage from the local oscillator 3 to the waveguide 8 side.

FIGS. 2a and 2b show another embodiment of the MIC converter according to the present invention, and the same parts as in FIGS. 1a and 1b are given the same numbers and will be described. Configured with MIC
SHF amplifier 1, frequency mixer 2, local oscillator 3
are formed on one dielectric substrate 4, and the SHF amplifier 1 is connected to a frequency mixer 2, and the frequency mixer 2 is connected to a local oscillator 3, respectively, and arranged in the same shield case 5. Reference numerals 9 and 10 designate metal partition plates, which are disposed inside the shield case 5, and the metal partition plate 9 spatially separates the SHF amplifier 1 and the frequency mixer 2, and the metal partition plate 10 constitutes the SHF amplifier 1. The front stage amplifier 1a and the rear stage amplifier 1b are spatially separated. Other than that, it is the same as FIG. 1.

In the embodiment of the present invention, in addition to the effects of the embodiment of FIG. 1, that is, the effect of simplifying the design of the SHF amplifier 1 and the effect of reducing unnecessary radiation leakage,
A part of the local power of the local oscillator 3 propagates directly inside the shield case 5 and passes through the conductor post 7 to the waveguide 8.
Since it prevents leakage to the side, it has the effect of further reducing unnecessary radiation leakage. Furthermore, when the number of stages of the SHF amplifier 1 increases, it also has the effect of preventing instability of the amplifier due to the return of the signal from the output side to the input side 1.

FIGS. 3a and 3b show another embodiment of the MIC converter according to the present invention, and the same parts as in FIGS. 2a and 2b are given the same numbers and will be described. 11, 12, and 13 are radio wave absorbers made of ferrite rubber or the like. The radio wave absorber 11 is a space 1 in which the front stage amplifier 1a is surrounded.
4 and further away from the input signal propagation line. The radio wave absorber 12 is placed in a space 15 surrounding the rear-stage amplifier 1b, and further away from the input signal propagation line. The radio wave absorber 13 is arranged in a space 16 surrounding the frequency mixer 2 and local oscillator 3. In particular, when the frequency mixer 2 includes an image signal blocking filter, the radio wave absorber 13 is arranged near the image signal blocking filter of the frequency mixer 2. For example, although FIG. 3c shows only two parts of the frequency mixer including the image signal rejection filter, the image signal rejection filter is comprised of three open-ended stubs. And radio wave absorber 1
3 is located near the open end of the open-ended stub. Other than that, the configuration is exactly the same as in FIG.

In the embodiment of the present invention, in addition to the effects of the embodiments shown in FIGS. 2a and 2b, that is, the effect of simplifying the design of the SHF amplifier 1 and the effect of reducing unnecessary radiation leakage, the shield case 5 and the metal partition plates 9 and 10 are Since the unnecessary resonance phenomenon inside the shield case 5 caused by This has the effect of preventing the frequency characteristics of loss and image suppression ratio from becoming unstable and from having unnecessary resonance characteristics. At the same time, the local oscillator 3 has the effect of suppressing a phenomenon in which local power is not sufficiently applied to the mixer diode of the frequency mixer 2. The radio wave absorbers 11 and 12 also have the effect of reducing unnecessary radiation leakage from the local oscillator 3 to the waveguide 8 side.

FIGS. 4a and 4b show another embodiment of the MIC converter according to the present invention, and the same parts as in FIGS. 3a and 3b are given the same numbers and will be described. A metal block 17 is provided to narrow the width of a space 14' in the shield case 5 in which the front stage amplifier 1a is surrounded.
The radio wave absorber 11 that is arranged in FIGS. 3a and 3b is not arranged in the embodiment shown in FIGS. 4a and 4b. Other than that, the configuration is exactly the same as in FIGS. 3a and 3b.

In the embodiment of the present invention, in addition to the effects of the embodiments shown in FIGS. 2a and 2b, the metal block 17 narrows the width d of the space 14' inside the shield case 5.
The unnecessary resonance frequency occurring within the space 14' moves from within the frequency band used by the MIC converter or near the band to far outside the band, and the adverse effects of the unnecessary resonance phenomenon on the frequency characteristics of the gain of the input VSWR of the MIC converter are removed. . At the same time, this has the effect of preventing deterioration of the noise figure of the MIC converter. The radio wave absorber 12 has the effect of suppressing unnecessary resonance phenomena occurring in the space 15 in which the rear-stage amplifier 1b is housed, and at the same time reducing unnecessary radiation leakage from the local oscillator 3. Since the radio wave absorber 13 has the effect of suppressing unnecessary resonance phenomena occurring within the space 16 in which the frequency mixer 2 and the local oscillator 3 are accommodated, the conversion loss and image suppression ratio of the frequency mixer 2 are adversely affected. This has the effect of eliminating the phenomenon in which the local power of the local oscillator 3 is not sufficiently applied to the mixer diode of the frequency mixer 2. For example, the frequency used is 11.7~12.5GHz.
In the MIC converter, the width of the shield case 5 is 30 mm, the height is 9 mm, and the length of the space 14' is 23.5 mm.
By installing a metal block 17 with a width of 7 mm, the unnecessary resonance frequency that was around 12.5 GHz when the
Moved out of the 12.9GHz band. The noise figure is improved by 0.1 to 0.2 dB by using the metal block 17 instead of the radio wave absorber 11.

FIGS. 5a and 5b show another embodiment of the MIC converter according to the present invention, and the same parts as in FIGS. 4a and 4b are given the same numbers and will be described. 17 and 18 are metal blocks. The metal block 17 is provided to narrow the width of the space 14' in the shield case 5 in which the preamplifier 1a is surrounded.
is provided to narrow the width of the space 15' within the shield case 5 surrounding the rear-stage amplifier 1b. The radio wave absorber 12, which is arranged in FIGS. 4a and 4b, is not arranged in the embodiment shown in FIGS. 5a and 5b. Other than that, the configuration is exactly the same as in FIGS. 4a and 4b.

In the embodiment of FIGS. 5a and 5b according to the present invention, in addition to the effects of the second embodiment, metal blocks 17, 1
Space 1 in which SHF amplifier 1 is accommodated by 8
Since the unnecessary resonant frequencies generated within 4' and 15' are moved far outside the frequency band used by the MIC converter, adverse effects on the frequency characteristics of the input VSWR, gain, and noise figure of the SHF amplifier 1 are eliminated. Furthermore, the effects of the radio wave absorber 12 are as shown in Figure 3a.
The effects of the embodiments shown in FIG. 4b or FIGS. 4a and 4b are the same.

FIG. 6 shows another embodiment of the MIC converter according to the present invention, and the same parts as in FIGS. 1a and 1b are given the same numbers and will be described. A SHF amplifier 1, a frequency mixer 2, and a local oscillator 3, which are each composed of an MIC, are formed on a single dielectric substrate 4.
are connected to the same shield case 5.
located within. Reference numeral 6' denotes an input strip line for the SHF amplifier 1, which is formed on the dielectric substrate 4 together with the SHF amplifier 1. One end of the input strip line 6' is connected to the SHF amplifier 1, and the other end is connected to the waveguide 8'. It is protruding inward. The ground conductor of the dielectric substrate 4 is removed from the portion of the input strip line 6' that protrudes into the waveguide 8'. In this way, the input stripline 6' itself constitutes a line converter from the waveguide 8' to the input stripline 6'. Input strip line 6'
The length of the distance l' from the point C protruding into the waveguide 8' to the end wall surface B-B' of the shielding case 5 is:
It is selected to be approximately 1/2 of the propagation wavelength λg of the input signal and local oscillation signal within the shield case 5. Here, the propagation wavelength λg within the shield case 5 refers to the wavelength at which the signal propagates on the strip line formed on the dielectric substrate 4 or the wavelength at which the signal propagates directly within the shield case 5.

The effect of the embodiment of FIG. 6 according to the present invention is the same as that of the embodiment of FIGS.
The part closest to B', that is, from the point C where the input strip line 6' protrudes into the waveguide 8' to the point C' where the input strip line 6' is bent at an angle of 90 degrees. This part becomes an equivalent short-circuit surface for the waveguide mode propagating inside the shield case 5 (the mode propagating in the left-right direction inside the shield case 5 in Fig. 6), and from point C to point C' there is no waveguide mode. The electric field strength of the wave tube mode becomes zero, and the input strip line 6' and the propagation mode in the shield case 5 are coupled at the discontinuous part of the input strip line 6' from point C to point C'. Due to the discontinuous part (the part from point C to point C') existing in the input strip line 6', coupling between the SHF amplifier 1 and the propagation mode in the shield case 5 occurs, and the SHF amplifier 1 Since the influence of the input impedance of the input impedance becoming unstable due to the shield case 5 can be reduced, the SHF amplifier 1 can be easily designed regardless of the presence or absence of the shield case 5. At the same time, it has the effect of reducing unnecessary radiation leakage from the local oscillator 3 to the waveguide 8' side.

FIG. 7 shows another embodiment of the MIC converter according to the present invention, and particularly relates to the structure of the shield case 5, and the same parts as in FIGS. 5a and 5b are given the same numbers and will be described. The shield case 5 in FIGS. 5a and 5b includes a bottom case 19 and a top case 2.
It is divided into two parts, 0 and 0. The dielectric substrate 4 is placed on the flat bottom case 19, and the bottom case 19 is placed so that the top case 20 surrounds the dielectric substrate 4.
placed above. The metal partition plates 9, 10 and the metal blocks 17, 18 are constructed integrally with the upper lid case 20.

FIG. 8 is a perspective view of the upper lid case 20, and as shown in the figure, the metal partition plates 9 and 10 and the metal block 1
7 and 18 are integrated with the upper lid case 20.
Recesses 9' and 1 provided in metal partition plates 9 and 10
A strip line runs through 0',
The dimensions of the recesses 9' and 10' are selected to be smaller than λg/2 in order to improve the partitioning effect, and the dimensions of the recesses 9' and 10' are selected to be smaller than λg/2 in order to improve the partitioning effect, and in order not to greatly disturb the characteristic impedance of the strip line. It is selected to be as wide as about twice the width of the strip line in the direction, and to be as high as about three times as high as the thickness d of the dielectric substrate 4 in the height direction. Metal partition plates 9 and 10 and metal block 1 integrated into upper lid case 20
7 and 18 are raised from the bottom of the upper lid case by the thickness d of the dielectric substrate 4.

In the embodiment shown in FIG. 8, the metal partition plates 9 and 10 and the metal blocks 17 and 18 are integrated with the upper lid case 20, so a dielectric substrate is provided for each space divided by the metal partition plates 9 and 10. No need to divide. Therefore, on one dielectric substrate
SHF amplifier 1, frequency mixer 2 and local oscillator 3 can all be formed, and dielectric substrate 4
This has the effect of improving the mass productivity of the microwave integrated circuit configured above. At the same time, metal partition plates 9, 1
0 and metal blocks 17, 18 are integrated with the top case 20, and the bottom case 19 is flat, making handling of the shield case and attachment of the dielectric substrate 4 to the bottom case 19 easier.
Furthermore, since the dielectric substrate 4 can be crimped onto the bottom case 19 by the top case 20, there is also the effect of improving the reliability of fixing the dielectric substrate 4 onto the bottom case 19.

FIG. 9 shows the essential parts of another embodiment of the MIC converter according to the present invention, particularly regarding the positional relationship of the recesses 9', 10' of the metal partition plates 9, 10 with respect to the strip line. 21 is a DC blocking circuit;
When the open-ended strip line of the book is connected to the open end of the open-ended strip line, approximately 1/4 wavelength of the input signal (1/4
A 1/4 wavelength line-coupled interdigital DC blocking circuit is used which is distributed and coupled over the length of λ _s Metal partition plates 9 and 10 are arranged so as to be aligned with each other. This DC blocking circuit 21 can also be used as a DC blocking circuit that separates the SHF amplifier 1 and the frequency mixer 2 in terms of DC.
Alternatively, it is also used as a DC blocking circuit that separates the front-stage amplifier 1a and the rear-stage amplifier 1b that constitute the SHF amplifier 1 in terms of DC.

In the embodiment shown in FIG. 9, even if the dimensions of the recesses 9' and 10' of the metal partition plates 9 and 10 are the same, the metal partition plates 9 and
10 on the characteristic impedance of the strip line is due to the recesses 9' and 1 of the metal partition plates 9 and 10.
Compared to when 0' is on a normal strip line,
It has been experimentally confirmed that the number is smaller in the embodiment shown in FIG. Therefore, even if the effect of the partitions is the same, the embodiment shown in FIG. 9 has the effect of reducing the effect that the metal partition plates 9 and 10 have on the characteristic impedance of the strip line and ultimately on the characteristics of the microwave integrated circuit. have On the contrary, the effect of the partition can be improved while minimizing the influence of the metal partition plates 9 and 10 on the strip line.

Effects of the Invention As described above, according to the present invention, the SHF amplifier,
Alternatively, since the input impedance of the MIC converter is less likely to change with or without the shielding case, even if the SHF amplifier is designed without the shielding case and is covered with the shielding case, the SHF amplifier will not change. input impedance characteristics are not affected. Accordingly
SHF amplifier design becomes easier.

[Brief explanation of drawings]

FIGS. 1 a and b are a sectional plan view and a side sectional view showing one embodiment of the MIC of the present invention, and FIGS. 2 a and b are a sectional plan view and a sectional side view showing another embodiment of the MIC of the present invention. , FIGS. 3 a to 3 c are plan sectional views, side sectional views, and main part plan views showing still other embodiments of the MIC of the present invention, and FIGS. A plan sectional view and a side sectional view showing still other embodiments of the MIC, FIG. 6 is a side sectional view of the same,
Fig. 7 is a side view of the same, Fig. 8 is a perspective view of the same main part, Fig. 9
The figure is a plan view of essential parts showing still another embodiment of the MIC of the present invention. 1...SHF amplifier, 2...frequency mixer, 3
...Local oscillator, 5...Shield case, 6,
6'...Input strip line, 7...Conductor post,
8, 8'... Waveguide, 9, 10... Metal partition plate,
11, 12, 13... Radio wave absorber, 14, 14',
15, 15', 16...Space, 17, 18...Metal block, 20...Top cover case, 21...DC blocking circuit.

Claims (1)

[Claims] 1. On a microwave integrated circuit board, an SHF amplifier,
A frequency mixer and a local oscillator are connected in this order, at least the SHF amplifier is placed in a shielded case, a line converter to another line is connected to the input strip line of the SHF amplifier, and the input strip line is connected to the input strip line of the SHF amplifier. and a connecting point of the line converter is provided at a position approximately λg/2 (λg is a propagation wavelength within the shielding case) from an end wall surface of the shielding case. 2. A patent claim characterized in that a metal partition plate is arranged in the shield case to spatially partition an SHF amplifier and a frequency mixer, and a metal partition plate is also arranged between amplification elements that constitute the SHF amplifier. The microwave integrated circuit according to item 1. 3. The microwave integrated circuit according to claim 2, characterized in that a radio wave absorber is disposed in each space within the shield case partitioned by a metal partition plate. 4 Among the spaces in the shield case partitioned by metal partition plates, a radio wave absorber is arranged in each space other than the space where the input strip line of the SHF amplifier is arranged, and the input strip line is arranged. 3. The microwave integrated circuit according to claim 2, wherein the width of the space is narrowed. 5. The shield case is divided into a bottom case on which the microwave integrated circuit board is mounted, and a top case that integrates the side and top parts of the shield case, and a metal partition plate is integrated with the top case. The microwave integrated circuit according to claim 2, characterized in that: 6 On the microwave integrated circuit board, SHF amplifier,
A frequency mixer having an image signal blocking filter and a local oscillator are connected in this order, and at least the SHF amplifier and the frequency mixer are arranged in a shield case.
A metal partition plate is arranged to spatially partition the SHF amplifier and the frequency mixer, and the SHF
A metal partition plate is also arranged between the amplification elements constituting the amplifier, and a radio wave absorber is arranged in each space in the shield case partitioned by the metal partition plate,
The radio wave absorber placed in the space partitioned by the frequency mixer is placed near the image signal blocking filter, and a line converter to another line is connected to the input strip line of the SHF amplifier. and a connection point between the input strip line and the line converter is provided at a position approximately λg/2 (λg is the propagation wavelength within the shield case) from the end wall surface of the shield case. wave integrated circuit. 7 On the microwave integrated circuit board, the SHF amplifier,
A frequency mixer and a local oscillator are connected in this order, at least the SHF amplifier is disposed within a shield case, and a metal partition plate is disposed within the shield case to spatially partition the SHF amplifier and the frequency mixer. At the same time, a metal partition plate is also arranged between the amplifying elements constituting the SHF amplifier, and a line converter to another line is connected to the input strip line of the SHF amplifier, and a line converter for connecting the input strip line to the line converter is connected to the input strip line of the SHF amplifier. The connection point of the device is located at a distance of about λg/2 (λg is the propagation wavelength within the shielding case) from the end wall surface of the shielding case,
The shield case is divided into a bottom case on which the microwave integrated circuit board is mounted, and a top case that integrates the side and top parts of the shield case, and the width of the metal partition plate and the space are narrowed. A microwave integrated circuit characterized in that a conductive plate or a metal block is integrated with the upper case. 8 On the microwave integrated circuit board, SHF amplifier,
A frequency mixer and a local oscillator are connected in this order, at least the SHF amplifier is disposed within a shield case, and a metal partition plate is disposed within the shield case to spatially partition the SHF amplifier and the frequency mixer. At the same time, a metal partition plate is also arranged between the amplifying elements constituting the SHF amplifier, and a line converter to another line is connected to the input strip line of the SHF amplifier, and a line converter for connecting the input strip line to the line converter is connected to the input strip line of the SHF amplifier. The connection point of the device is located at a distance of about λg/2 (λg is the propagation wavelength within the shielding case) from the end wall surface of the shielding case,
The metal partition plate that spatially partitions the SHF amplifier and the frequency mixer is placed on a DC blocking circuit formed of a strip line that isolates the SHF amplifier and the frequency mixer in terms of DC,
A microwave integrated circuit characterized in that the metal partition plate between the amplification elements constituting the SHF amplifier is placed on a DC blocking circuit formed of a strip line that isolates the amplification elements in terms of DC. .