JPS6036645B2 - oscillator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oscillator, and more particularly to a multi-frequency switching oscillator used in a transmitter/receiver of a microwave or millimeter wave communication device.

BACKGROUND ART As a highly stable oscillation source used in microwave and millimeter wave communication devices, any one of a plurality of oscillation frequencies is selectively switched and used.

FIG. 1 is a block diagram showing an example of a slave multi-frequency switching oscillator which is the background of the present invention.

In FIG. 1, independent oscillators 21 and 2
2,...2n are provided. And these oscillators 2
1, 22, . . . 2n have different oscillation frequencies fl, f2, . These oscillators 21,
22, . . . 2n have power switches 11, 12 . ...l
It is connected to a voltage source via n. Also, oscillator 2
The outputs of 1, 22, . and,
One of these oscillators 21, 22, ... 2n is selected by turning on one of the power switches 11, 12, ... ln, and the output of the selected oscillator is given to the load 4. There is. Since the conventional multi-frequency oscillator is configured in this manner, a plurality of oscillators each having an independent and different oscillation frequency are required.

Therefore, a plurality of active elements are also required for these oscillators. Therefore, such a multi-frequency switching oscillator becomes extremely expensive. At the same time, in microwave oscillators and the like, there are certain limits to miniaturization of each individual oscillator. Therefore, if a plurality of independent oscillators are used in this way, the oscillator will be extremely large. Therefore, it is also difficult to miniaturize a transceiver using such an oscillator. Therefore, the main object of the present invention is to provide an inexpensive and compact multi-frequency oscillator.

To summarize, this invention connects a transmission line to the gate terminal of an active element having negative resistance characteristics, such as a field effect transistor (hereinafter referred to as "FET") whose drain is grounded, and terminates the other end with a non-reflection terminator, thereby transmitting This is an oscillator in which a plurality of mutually uncoupled resonators with a predetermined resonance frequency are arranged at appropriate positions on the line, and the oscillation frequency is selected by changing the phase conditions of these plurality of resonators. .

The above objects and other objects and features of the invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 2 is a circuit diagram showing an embodiment of the present invention.

In the configuration, one FETIIO is provided. This FETIIO includes a gate terminal 111, a source terminal 112, and a drain portion 113. Drain terminal 113 is grounded. A transmission line 121 is coupled to the gate terminal 111. This transmission line 121 is composed of, for example, a strip line, and includes n resonators 131, 132, . . . , 13n, each having a different vibration or resonance frequency.
are combined. This strip line, that is, the transmission line 121 is terminated with a non-reflection terminator 140 at the other end. Further, a varactor diode 150 is connected to the transmission line 121. An external signal is applied to this varactor diode 150 from an external signal applying means (not shown), and its interelectrode capacitance is changed. An output plug 160 is connected to the source terminal 112 of the FETI IO via a transmission line 122. In such a configuration, the varactor diode 15
By applying an external signal to each resonator 131,
132,...13n and FETII
Change its electrical length so that it forms an oscillation circuit with O. As a result, the oscillation frequency obtained from the oscillator 100 after the output from each resonator 131 and 13n
The oscillation frequency corresponds to one of the resonant frequencies. This will be explained in detail below with reference to FIGS. 3 and 4. FIG. 3 is an explanatory diagram when any one of a plurality of resonators is selected, and FIG. 4 is an equivalent circuit thereof.

A normalized impedance ZR (normalized by Zo) looking into the resonator and non-reflection terminator 140 from the resonator coupling point A is expressed by equation '1}.

ZR=・Jukobokisu ---'1'Here, Q
.

= of. C. R. (No-load Q of the resonator).

= Maro 6 (resonant frequency of the resonator) 6 = 22, etc. (degree of detuning) 0 li.

Therefore, the reflection coefficient rR at point A is expressed by equation (2).

rR=(r.

12 antiques 6. ．．・F expected from '21 point B
The reactance component of the input impedance of ET110 is included in the transmission line length 6, and if xG=0, then Z
G2rG(ku0)...If it is '3', the reflection coefficient rc (corresponding to the S parameter S,.) is r.

= Takuton -.・[It is 4'.

In a common drain FET, internal feedback occurs due to the capacitance between the source and gate, rG<0, and if there is no resonator, it becomes a negative resistance amplifier.

When rR approaches 1 at point A, negative resistance oscillation occurs. The oscillation conditions are expressed by the following equation '5'. rR・r
Ge-j2821...(5} Formula [2}, formula (4') is substituted and rearranged: r.

Fukiai・(r.

12) cos20-28.6sin2a(r.

1270 (28.6 a) -h.

Takuzo 28.

6cos280 (r.

12) sin28 and (r. 1270 (2806a), and when the oscillation frequency condition is determined from the imaginary part, the following equation {6- is obtained.

6=-(r.

12) tan28…[6}28
. By substituting equation (6) into the real part, the following equation '7} is obtained.

r. Yoshizo et al. 20S2821 ---'71 Complaints<o ---Mi cos28 Mi Tate 2, "Satiri
...'8, - r.

If rG-・Yoshizo≧o Manabu/Imozo ≦ COS male 1. ．．・[91 becomes.

Formula {In the case of 81, Gei-M≦8 No. 10M (assumed to be aS2)
In the case of the formula {9-, the oscillation condition is satisfied within the range of OS8≦Ge-M or the range of 10M, 2, and 2 (wet).

According to the actual measured value of the input impedance of FETIIO, r
Since G=-0.1, the conditions for starting oscillation are as follows:
To give a numerical example of the formula leg, when 6 = 0, the VSWR when looking at the resonator and non-reflection terminator from point A is p = 10r.

Since it can be expressed as r in formula (■). =p-1, and if negative resistance rc=-0.1 and p=17, then r+2. rG+
1=・0.92 ro rc−1, and therefore 78.50SOSIOI. 50
...(It can be seen that oscillation occurs within the range of 1, but oscillation stops outside this range.

Figure 2 shows a varactor 11 diode 150 so that the electrical angle 8i between the gate terminal and the resonator can be varied by an external signal.
This is an example of a configuration in which .

A line 121 coupled to a gate terminal 111 is coupled to n dielectric resonators 131 to 13n. The phase 8i between the gate terminal 111 and each resonator is always outside the range indicated by the square foot, and the negative resistance of FET II0 is terminated with a non-reflection terminator. When an output of frequency fi is desired, the voltage applied to the varactor diode 150 is changed so that the i-th resonator 13i satisfies the oscillation condition (2) and obtains an output of frequency fi. In the embodiment shown in FIG. 2 (FIGS. 3 and 4), the oscillation conditions of each resonator are selected by electrically changing the phase length between the gate terminal 111 of the FET IIO and each of the resonators 131 to 13n. However, the physical length between the gate terminal 111 and each resonator may be fixed, and the resonant frequency of each resonator may be detuned.

FIG. 5 shows such an embodiment. In FIG. 5, the transmission line 121 similarly includes n resonators 131, 1
32,...13n are connected.

These resonators 131, 132, ... 13n include a second
transmission lines 171, 172, . . . 17n are coupled. Then, second transmission lines 171, 172,...
PIN diodes or varactor diodes 181, 182, . . . 18n are connected to the terminals of 17n. Therefore, in the embodiment of FIG. 5, the varactor diode 150 used in the embodiment of FIG. 2 is not used.
Now the electric angle is expressed as Ma = BI = Z child 1 = 2 Bamboo air force fl.

Enter here.

: Free space wavelength Eeff: Effective yield rate of planar circuit c: speed of light 1: FET gate status and current thoughts Physical length of shaker f: Resonant frequency.

Substituting Equation (11) into Equation '10 to find the frequency that satisfies the oscillation conditions gives C C 78.502 mzoEef-, ≦f≦101. ? Hiroshi 7th string cloth...(12).

c=3×1bi1 skin, Eeff=2.21, 1=7 side 6. & day 2 mi fS8.10Hz...
・(13) becomes.

Therefore, from equation (13), 7. A resonator having a resonant frequency of 2 days per day satisfies the oscillation condition within 190 days 2 when 1 is constant, but the oscillation condition is not satisfied if the resonance frequency is detuned outside this range. FIG. 6 shows an equivalent circuit when the second transmission line is coupled to the resonator.

If any of the PIN diodes 181 to 18n is now short-circuited, the impedance when looking to the right of point C is L of Z'=i.

≧. T Hiroshi. Kozo. Rod quality: k2)...(・4). Here, k is a coupling coefficient and is expressed as k=Rozo.

Assuming that a′=n, Z': L of j.

(1-k2) ...(15). Therefore, the resonance frequency is expressed by the following equation (16). 1
．． ．． ．． (16)=zo(1-k2)L.

C. Also, if any of the PIN diodes 181 to 18n is left open, the L of Z'nij.

-ZOC. t80 L(11k2)...(17)-Z. c.
ot80wL, 8'=n, coto=, so Z'nij's L.

...(18), and the resonant frequency at this time is 1. ．． ．． It becomes the 27q branch of (i9).

This is the resonant frequency specific to the resonator. Therefore P.I.
By turning on and off any one of the N diodes 181 to 18n using an external signal, a change ratio of the resonance frequency can be obtained by 1-k2. When k=0.57. The frequency change in the phantom HZ is about IGHZ. Therefore, when the PIN diodes 181 to 18n are short-circuited, the equation (1)
The resonator is modeled so as not to satisfy the oscillation condition of 2), and when desired, one of the PIN diodes 181 to 18n is opened to satisfy the oscillation condition at the resonant frequency unique to the resonator. If you keep it, your purpose will be fulfilled. Also, with the PIN diodes 181 to 18n open,
The purpose can also be achieved by tuning the resonator and short-circuiting any of the PIN diodes 181 to 18n when desired to achieve a resonant frequency specific to the resonator.
As described above, according to the present invention, since the oscillator is constructed by selecting a plurality of resonators using only one active element, such as a FET, an inexpensive and small multi-frequency switching oscillator can be obtained. It will be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a slave multi-frequency switching oscillator which is the background of the present invention. FIG. 2 is a conceptual diagram showing an embodiment of the present invention. Third
The figure is a conceptual diagram when one resonator is selected in the embodiment of FIG. 2, and FIG. 4 shows its equivalent circuit. FIG. 5 is a conceptual diagram showing another embodiment of the present invention, and FIG.
The figure is an equivalent circuit for explaining the embodiment. In the figure, 11 is a FET, 121 is a transmission line, 131 is not provided, 13n is a resonator, 14 is a non-reflection terminator, 150
is a varactor diode, 160 is a plug after the output, 171 is not provided, 17n is a second transmission line, 181 to 18n are P
Indicates an IN diode or varactor diode. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. A field effect transistor whose drain is grounded, a transmission line whose one end is coupled to the gate terminal of the field effect transistor, a non-reflection terminator provided at the other end of the transmission line, a plurality of mutually uncoupled resonators each individually coupled to a transmission line and each having a predetermined resonant frequency; and selecting any one of the plurality of resonators together with the field effect transistor. An oscillator comprising selection means constituting an oscillation circuit. 2. The selection means includes an element that is provided at an appropriate position on the transmission line between the gate terminal of the field effect transistor and each resonator and that electrically varies reactance, and means for applying an electric signal to the element. Claim 1 containing
Oscillator mentioned in section. 3. The selection means includes a second transmission line coupled to each resonator, an element provided at one end of the second transmission line and capable of electrically varying reactance, and applying an electric signal to the element. An oscillator according to claim 1, comprising means. 4. The selection means includes a second transmission line coupled to each resonator, an element provided at one end of the second transmission line and capable of electrically shorting or opening, and applying an electric signal to the element. 2. An oscillator according to claim 1, further comprising means for shorting or opening. 5. The oscillator according to any one of claims 1 to 4, wherein the transmission line is composed of a stripline, and each of the resonators is composed of a dielectric resonator.