JPS6014533B2 - How to combine the output power of multiple oscillators - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for combining the output power of a plurality of oscillators using a four-terminal father-to-back 90o coupler.

Many techniques have been proposed for synthesizing the outputs of multiple microwave or millimeter wave oscillators in the same phase.

As a method using a 4-terminal 3-9 coupler, the first coupler
A fourth method is to connect a passive impedance to the terminal of the oscillator and couple the outputs of the oscillators to be synthesized to the second and third terminals, respectively, to obtain the synthesized output.

In a circuit that implements this method, when optimally adjusted, the power output to the first terminal is almost zero, and is extremely weak.

Since this weak power is reflected by a passive impedance, divided into two equal parts, and injected into each oscillator as an injection locking signal, the injection locking signal is weak and there is a problem in the stability of the circuit's locking operation. Also known is a 2N oscillator output power synthesis method that repeatedly uses the two-oscillator power synthesis method described above. However, this method has a drawback that as the number of coupling stages N increases, the power combining efficiency decreases due to the loss of the coupler. Also, conventionally,
Known methods for combining oscillator output power by connecting oscillators in a dependent or series manner include a method using a circulator and a method using a directional coupler in which the degree of coupling is different for each stage.

Both methods have the disadvantage that the power combining efficiency rapidly decreases as the number of coupling stages increases due to losses in the circulators and directional couplers. SUMMARY OF THE INVENTION An object of the present invention is to provide a novel method for combining the output power of multiple oscillators, which can solve all of the above-mentioned problems.

To achieve the above object, the present invention provides a method for combining the outputs of multiple oscillators by combining the first, second,
The third terminal is configured to connect oscillator outputs having substantially the same level of output that can be mutually injection-locked, and to obtain a combined output corresponding to the sum of the respective oscillator outputs from the fourth terminal. ing.

According to the above configuration, compared to the conventional method, injection locking is reliable and efficient power synthesis is possible.

Furthermore, by expanding the basic concept of combining the outputs of three oscillators, it becomes possible to combine the outputs of a large number of oscillators. As will be described later, adjustment is easy, and industrial application is easily possible. Note that in the present invention, the term oscillator is
The term ``element oscillator'' is used to include individual oscillators called element oscillators and devices that generate an output that is a combination of their outputs. The method of the present invention will be described below with reference to the drawings, its principles, etc.
and examples will be explained in order.

FIG. 1 is a schematic diagram for explaining the principle of a three-oscillator output synthesis method.

In FIG. 1, the oscillation frequency of oscillator a is assumed to be 0, and the output power thereof is assumed to be Pa. Power Pa enters the coupler from terminal 1 of the coupler, and according to the characteristics of the old $900 coupler A, it is divided into two, Pa/2 goes out to terminal 2, Pa/2 goes out to terminal 3,
Moreover, the phase of the power wave output from terminal 3 lags the phase of the power wave output from terminal 2 by 90 degrees. The power output to terminals 2 and 3 is injected into oscillators a and oscillators b, respectively. At terminal 2, when the free-running oscillation frequency 8b of oscillator b is sufficiently close to the cape, a synchronous pull-in phenomenon occurs, and oscillators a and oscillators oscillate synchronously at a single frequency f.

The output of oscillator b operating in the synchronous pull-in state depends on the detuning frequency f - fb from the resistance of f, and takes a maximum value at a certain oscillator frequency, and that value is approximately equal to the output power of the running oscillator of oscillator b. The value is the sum of Pb and the injection power Pa/2. terminal 3
Since oscillator c having characteristics similar to oscillator b is connected to oscillator b, the same phenomenon as described above occurs in case 3 with a phase delay of 90°.

As a result, a fin force wave carrying a power of Pb+Pa/2 is sent from the terminal 2 to the coupler A, and a power wave carrying a power of Pc+Pa/2 is sent from the terminal 3 with a phase delay of 9 degrees. Here, Pc is the output power of the oscillator c during free-running oscillation. Since oscillators b and oscillators c have similar characteristics, they are Pb and Pc. These power waves are sent to terminals 1 and 4, respectively, according to the characteristics of the three old 90o couplers described above. At terminal 1, the phases of the power waves sent from terminals 2 and 3 have a difference of 1800 degrees, and they cancel each other out, so that the power injected back into the oscillator a becomes zero. On the other hand, at terminal 4, the power waves sent from terminals 2 and 3 are added in phase, and a composite power of a value close to Pa + Pb + PC is supplied to load d. The method presents three methods that can be extended to output power combination of multiple oscillators.

The first method is to replace oscillators a and byc in Figure 1 with three oscillator coupling circuits in the next stage, and in the case of N stages,
The outputs of 3N oscillators can be combined in power by (3N-1)/2 couplers. A multi=9 oscillator coupling circuit is shown in FIG. In FIG. 2, 21 to 29 are oscillators whose power is combined, 20 is a load, and A to D are couplers. The second method is to replace oscillator a in FIG. 1 with a three-oscillator coupling circuit in the next stage, and in the case of N stages, the outputs of eleven oscillators can be combined in power by N couplers.

A 2×41=9 oscillator coupling circuit is shown in FIG.

In FIG. 3, 31 to 39 are oscillators, 30 is a load, and A to D are couplers. The third method is to connect M state oscillator coupling circuits, which are obtained by removing the oscillator 32 and load 30 from the Nobi 11 oscillator coupling circuit shown in FIG. This is a method of configuring an oscillator coupling circuit.

FIG. 4 shows a 2×4×21=17 oscillator coupling circuit in the case of N=4 and M=2. In Figure 4, 41 and 42 are 2 x 4 =
8 oscillator coupling circuits, 43 and 44 are two-branch power dividers/combiners, 45 is a master oscillator, 46 is a load, and 47 and 48 are non-reflection matching terminal devices. Next, specific configurations for implementing each of the above methods will be sequentially explained.

FIG. 5 is a perspective view showing the state of a short slot coupler, which is an example of a coupler used in the method of the present invention. In FIG. 5, 51 and 52 are rectangular waveguides, and 53 is a coupling window formed by removing a common narrow wall. The short slot coupler has a structure suitable for configuring a coupling circuit in a planar shape, and not only has a simple structure and is easy to manufacture, but also has a short line length, low loss, and broadband characteristics. Suitable as a combiner for synthetic circuits. FIG. 6 shows an example of a three-oscillator coupling circuit in which three serpentine Hz band Gunn oscillators are coupled by one short slot coupler.

In Figure 6, 61 has an inner dimension of 22. The rectangular waveguide on the Komisaki×10.2 side is shown. 62 is a waveguide flange of the coupling circuit output terminal, 63 is a connection flange between the oscillator section and the coupling window portion of the coupler, 64 is a coupling window, 65a, 65b, 65c are metal posts for mounting Gunn diodes, 66a, 66b, 66
c is a metal post that also serves as a DC bias terminal, 67a, 67
b, 67c are Gunn diodes, 68a, 68b, 68c
represents a dielectric rod for tuning the waveguide cavity.

During adjustment and use, the output terminal is connected to the load via a unidirectional tube. Perform circuit adjustment as follows.

First, only the oscillator a is operated, and the insertion length of the dielectric rod 68a is adjusted so that the frequency becomes close to the desired frequency f.
Next, oscillators b and oscillators c are added to the operation, and the insertion lengths of the dielectric bars 68b and 68c are alternately repeated so that the operation of the coupling circuit is in a synchronous oscillation state with a single frequency f and the output is maximized. If adjusted, a composite output power having a value close to Pa+Pb+Pc can be obtained at the operating frequency f. A Niji household gun diode was installed on the prototype circuit with the structure shown in Figure 6, and f was set to 973.
The results of five power synthesis experiments conducted using the 3M standard settings are shown in Table 1 at the end of the detailed description of the invention. In Table 1, Pa, Pb, and Pc are the power (W) supplied to the same load when oscillators a, b, and c are independently oscillated at f.
, P is the combined output power (skin W), and P = Pa + Pb +
Represents power combining efficiency defined as PCX100 (%).

In both examples, power synthesis efficiency of approximately 100% is obtained. Also, the detuning frequency of each oscillator △fi=fi−f,
The values of i=a, b, c are also shown. Insert a capacitive screw in the center of the coupling window and adjust its insertion length so that the phase angle of the coupler is exactly 9 pins.
It is thought that the following results can be obtained. FIG. 7 is a planar structural explanatory diagram showing an embodiment of a multi=9 oscillator coupling circuit.

The structure of the oscillator is similar to that shown in FIG. 6, using a snake diode. In Fig. 7, 71 is a rectangular waveguide, 72 is a coupling circuit output waveguide flange, 73 is a coupling window, 74 is a metal post for mounting a Gunn diode, and 75 is a dielectric rod for adjusting waveguide air-eye tuning. represent. In a power synthesis experiment at f = 962 MHz using this prototype circuit,
Salmon. A power combining efficiency of 4% (combined output of 194 mW) is obtained. FIG. 8 shows an example of a 2×41=9 oscillator coupling circuit, and is an explanatory diagram of the planar structure seen from above.

The structure of the oscillator is similar to that shown in FIG. 5, using a standard Gun diode. In FIG. 8, 81 is a rectangular waveguide, 82 is a coupling circuit output terminal waveguide flange, 83 is a connecting flange between the oscillator section and the coupler section, 84 is a coupling window, and 85 is a coupling circuit output terminal waveguide flange.
Reference numeral 86 represents a capacitive screw for adjustment to adjust the phase angle of the coupler to 9 pins, 86 represents a metal post for mounting a Gunn diode, and 87 represents a dielectric rod for adjusting the waveguide cavity Asaoka tuning. In a power synthesis experiment using this prototype circuit at f = 961 Hz, a power synthesis efficiency of 95.3% (combined output of 182 W) was obtained.
is obtained. In the above-mentioned embodiments, all short slot couplers were used as couplers, but there are various types of couplers that have four gates, a coupling degree of red B, and a phase difference of 90 degrees between outputs of common terminals. Among them, the couplers with the following names are considered to be particularly useful as couplers in the coupling circuit of the present invention. Useful in this order: [11 Short slot coupler (rectangular waveguide narrow-surface short slot coupler, also known as RjWet coupler) ■ Strip line x old directional coupler '31 Wide-area coupler (rectangular waveguide wide-surface short slot coupler) )'4
} Multi-coupling hole type Chiku B directional coupler (rectangular waveguide wide surface type and narrow surface type) In addition, in the above-mentioned embodiment, as an oscillator, one
1 with 1 gun diode installed in 2 oscillator pneumothorax
Although a cavity single element type oscillator is used, the present invention can also be applied to output power synthesis of a single cavity complex element type oscillator in which a plurality of elements are mounted in one cavity.

In this case, in addition to the advantage that the number of active elements whose power is combined increases significantly, there is also the advantage that the influence of a failure of one element in a certain pneumothorax on the overall combined output power can be reduced. Table 1 f=9733MHz

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram for explaining the principle of the 3-oscillator output synthesis method according to the present invention, and FIG. 2 is a circuit diagram for explaining the principle of the 3N oscillator output synthesis method with N coupling stages according to the present invention. 3 and 4 are circuit diagrams for explaining the principle of the (state+1) and (state M11) oscillator output synthesis method according to the present invention. FIG. 5 is a perspective view showing the concept of a short slot coupler which is one of the configuration examples of a coupler for carrying out the method of the present invention, FIG. FIG. 7 is a diagram showing an embodiment of a method for synthesizing the outputs of 3N oscillators, and FIG. 8 is a diagram showing an embodiment of the method of synthesizing the outputs of (state+1) oscillators. a, b, c: oscillator, d: load, 1, 2,
3, 4: first, second, third and fourth terminals of the coupler,
A, B, C, D: 4-terminal phantom B90o coupler, 21, 22
,...29: (Element) Oscillator 20 (d) Load, 3
1, 32,...39: (Element) Oscillator 30 (d) Load, 41, 42: 2x4 oscillator coupling circuit, 43, 44:
2-branch power distribution combiner, 45: Master oscillator, 46:
Load, 47, 48: Non-reflection matched terminator, 51, 52: Rectangular waveguide, 53: Coupling window, 61: Rectangular waveguide, 62, 6
3: Flange, 64: Combined window, 65a, 65b, 65c
: Metal post for mounting gun diode, 67a, 67b,
67c: Gunn diode (element oscillator), 68a, 68
b, 68c: dielectric rod for tuning adjustment, 71: rectangular waveguide,
72: Flange, 73: Coupling window, 74: Metal post for mounting gun diode, 75: Dielectric twill for adjustment, 81: Rectangular waveguide, 82, 83: Flange, 84: Coupling window, 85:
Capacitive screw for adjustment, 86: Metal post for mounting gun diode, 87: Dielectric bar for adjustment. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. Oscillator outputs of approximately the same level of output that are mutually injection-lockable are connected to the first, second, and third terminals of a four-terminal 3 dB 90° coupler, and the fourth terminal A method for synthesizing the output power of a plurality of oscillators to obtain a synthesized output corresponding to the sum of the outputs of the respective oscillators. 2. The plurality of oscillators according to item 1, wherein at least one terminal among the first, second, and third terminals of the coupler is connected to the oscillator outputs synthesized by the method described in item 1 above. Output power synthesis method. 3. The first, second, and third terminals of the coupler described in item 1 above are all connected to the final combined output from the fourth terminal of the lower coupler, and the first, The combined output from the fourth terminal of the lower coupler is connected to the second and third terminals, and this connection is repeated for the lower coupler to calculate the output power of the 3^N element oscillators. 2. A method for combining output powers of a plurality of oscillators according to claim 1. 4 Connect the output power from the fourth terminal of the lower coupler to the first terminal among the first, second, and third terminals of the coupler described in item 1 above, and connect the other two terminals to the element. The output of the oscillator is connected, and the output power from the fourth terminal of the further lower coupler is connected to the first terminal among the first, second, and third terminals of the lower coupler, and the output power from the fourth terminal of the lower coupler is connected. 2. The method for synthesizing the output power of a plurality of oscillators according to claim 1, wherein the output powers of (2N+1) element oscillators are synthesized by repeatedly connecting the outputs of the oscillators for each terminal.