JPS5919412A - Microwave oscillator - Google Patents

Abstract

PURPOSE:To make the characteristics stable and to simplify the constitution, by using a cut-off waveguide at an output terminal for preventing the abnormal oscillation. CONSTITUTION:An output of a basic wave oscillator 1 includes many harmonics because of the nonlinearity of a transistor (TR)3. In desiring to pick up the N-th harmonic, a waveguide 21 to cut off frequencies up to the (N-1)th harmonics is fitted to an output terminal of the basic wave oscillator 1. Further, a ridge 22 is provided to the cut-off waveguide 21 in order to attain excellent coupling to the N-th harmonic. It is possible to give a DC bias to the TR3 by fitting the ridge 22 floated from the waveguide 21 in terms of DC. Thus, no abnormal oscillation is produced, because the undesirable coupling is excluded in this way.

Description

Detailed Description of the Invention The present invention is an oscillation multiplication type microwave oscillator, that is, a microwave oscillator using an oscillation transistor. The present invention relates to an oscillation multiplication type microwave oscillator that extracts a frequency signal.

Conventional oscillation multiplication type microwave oscillators mainly consist of a fundamental wave oscillator using nine oscillation transistors and a multiplication circuit using multiplier diodes, etc., as will be explained in detail later. The configuration is complicated because the multiplier of and is directly connected to the fundamental wave oscillator, and the bias supply for the oscillation transistor of the fundamental wave oscillator uses a feedthrough capacitor. It also had many drawbacks, such as unstable characteristics.

Therefore, an object of the present invention is to provide an oscillation multiplication type microwave oscillator which has a simple structure and stable characteristics.

According to the present invention, an oscillation multiplication type microwave oscillation that extracts a signal at the Nth harmonic frequency (N is an integer of 2 or more) of the fundamental oscillation frequency generated by this circuit from the output of a microwave oscillator using a single oscillation transistor. In the apparatus, the Nth
The means for extracting the signal of the harmonic frequency is an output extraction waveguide that is cut off for frequencies up to the (N-1) harmonic frequency including the fundamental oscillation frequency, and the Nth harmonic frequency. Microwave oscillation characterized by comprising a cut-off waveguide made of glue horns for matching, and further comprising means for supplying the DC-J ear of the oscillation transistor via the ridge. A device is obtained.

Next, a detailed explanation will be given with reference to the drawings.

FIG. 1 is a partial cross-sectional view showing the configuration of a conventional multiplication type microwave oscillator. In Figure 1, ■ is a fundamental wave oscillator surrounded by a metal chassis, and 2 is a high Q for frequency stabilization.
resonator (in the configuration example shown in FIG. 1, a TEoIδ mode dielectric resonator is used, but a metal cavity may also be used); 3 is an oscillation transistor (Si transistor or GaAs FET) + 4 is a coupling strip line for electromagnetically coupling the high-Q resonator and the oscillation transistor; 5 and 6 are the base electrode lead wire and emitter electrode lead wire of the oscillation transistor 3, and the negative wire (St bipolar]/transistor)
or a gate electrode lead wire and a source electrode lead wire; 7.8 is a feedthrough capacitor for supplying DC bias to the oscillation transistor 3; 9 is a multiplier for generating harmonic components; 10 is for multiplication. diode.

11 is a resonant rod that constitutes a filter for extracting the necessary Nth modulus harmonic signal from the harmonic components; 12 is a coupling antenna that electromagnetically couples the fundamental wave oscillator 1 and the multiplier 9; and 13 is a coupling antenna. This is a feedthrough capacitor for biasing the multiplier diode 10.

However, the conventional microwave oscillator having such a configuration has the following drawbacks.

The first is that since the multiplier 9 is used, the multiplier diode 10. A holding mechanism for that diode.

In addition, mechanical parts such as the filter resonance rod 11 are required, which complicates the structure and increases the price.

Further, unnecessary oscillations at low frequencies (for example, about 100 to 300 MHz) are likely to occur due to the bias supply circuit of the multiplier diode IO, and to prevent this, the configuration becomes complicated and adjustment becomes difficult.

Second, since the fundamental wave oscillator circuit 1 and the multiplier 9 are directly connected, the load impedance of the fundamental wave oscillator 1 becomes the input impedance of the multiplier 9.

Since there is no buffering effect against impedance fluctuations between the two, impedance fluctuations of the multiplier 9 become load fluctuations of the fundamental wave oscillator 1. As a result, oscillation start-up characteristics, frequency fluctuations due to temperature changes, output level fluctuations, etc. tend to become unstable.

The third electrode is the electrode 6 of the first oscillation transistor 3 (emitter electrode in the case of a Si bipolar transistor, GaAs
In the case of a FET, the short-circuit surface position of the feedthrough capacitor 8 for supplying DC bias to the source electrode (source electrode) is likely to be uncertain, and the thickness and length of the conductor wire 14 between the feedthrough capacitor 8 and the electrode 6 are important. (5) The oscillation output level tends to change greatly depending on the location, etc.

Also, abnormal oscillations sometimes occur due to the feedthrough capacitor and conductor wire for bias supply.

Further, the capacitance of the feedthrough capacitor 8 may change greatly due to temperature changes, which also causes abnormal oscillation and leakage of microwaves to the outside.

FIG. 2 is a partial sectional view showing the configuration of an embodiment of the present invention, and (a) is a view seen from above with the upper part removed.

(b) shows a sectional view from the front. In FIG. 2, parts with the same functions as those in FIG. 1 are given the same reference numerals. The output circuit 20 replaces the multiplier 9 in FIG. In this output circuit 20, 21 is a waveguide for output extraction used in the present invention, and the input side of the waveguide is cut off for the fundamental oscillation frequency and unnecessary low-order harmonic signals. It is of shape. In this case, the length indicated by t in the figure is the cutoff size for the fundamental wave oscillation frequency and unnecessary low-order harmonics.

Reference numeral 22 is a glue horn for matching the desired N-th modulus harmonic signal to the waveguide 21 for output extraction described in "2".

(6) Electrode 6 of transistor 3 is connected. This ridge 22 is floated in direct current relation to the output waveguide 21 by the insulating sheet 23 and the insulating bushing 24, so that the terminal 25. A DC bias can be applied to the electrode 6 of the transistor through the Litz 22. With the above configuration, the necessary second harmonic can be extracted from the harmonic component generated by the nonlinear action of the transistor 3. Although the fundamental wave oscillator 1 has some features as the one shown in FIG. 1, the same reference numerals are used here.

As described above, the multiplier type microwave oscillator according to the present invention includes a waveguide 21 for output extraction having a shape that provides power and to-off for the fundamental wave oscillation frequency and unnecessary low-order harmonic signals, and a desired N-th modulus harmonic. It consists of a glue horn 22 for matching the wave signal to the output waveguide, and a terminal portion 25 using an insulating sheet 23 and a plate and a plate 24. Therefore, it is mechanically much simpler than the conventional device, and abnormal oscillations such as those caused by the multiplier diode and its bias supply circuit do not occur.
).

The output circuit 20 and the fundamental wave oscillator 1 are electromagnetically separated by a cutoff waveguide.

What is coupled to the output circuit by the Litz 22 is the Nth modal harmonic signal component of the fundamental oscillator 1, and there is a distance of 2d between the fundamental oscillation level of the fundamental oscillator 1 and the Nth modal harmonic signal level.
Since there is a conversion loss of B(T,〉0), the fundamental wave oscillator]
Since a 2 dB attenuator is inserted between the output circuit 20 and the output circuit 20, the influence of impedance fluctuations of the output circuit 20 on the fundamental wave oscillator 1 is greatly improved. For example, when extracting the second harmonic, the level difference (i.e., conversion loss) between the fundamental wave oscillation level and the second harmonic level is about 4 to 6 dB, so This is equivalent to inserting a dB attenuator between the output circuit 20 and the fundamental wave oscillator 1, which provides a buffering effect against impedance fluctuations in the output circuit 20, and reduces frequency fluctuations due to temperature changes in the oscillation starting characteristics of the fundamental oscillator 1. Output level fluctuations, etc. are improved (improvements for the above drawbacks of cylinder 2).

Furthermore, DC bias is supplied to the electrode 6 of the transistor 3 from outside through the terminal 25 and the ridge 22. The ridge 22 main body is connected to the external waveguide 2 by an insulating sheet 23.
6, which is floating in terms of DC.

At the same time, this insulating sheet 23 is used as a dielectric material.
2 and an external waveguide 26 constitute a capacitor, which is a short surface in terms of microwaves. Therefore, the microwave short surface position is determined.

The distance between the short surface and the transistor 3 is always constant, and abnormal oscillations and increases in microwave leakage due to temperature changes are greatly improved compared to when feedthrough capacitors are used in conventional devices. Furthermore, since the conductor wire 14 in the conventional example is not used, there are no changes in characteristics due to wire thickness, length, position, etc. (improvement over the above drawbacks of the tube 3).

As explained above, according to the present invention, it has become possible to improve many of the drawbacks of conventional devices.

(9)

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of a configuration example of a conventional microwave oscillation device, and FIG. 2 is a partial sectional view of a configuration example of an embodiment of the present invention, in which (a) is a view seen from above. , (b) are views seen from the front. Explanation of symbols = 1 is a fundamental wave oscillator, 3 is an oscillation transistor, 7 and 8 are feedthrough capacitors, 9 is a multiplier, 10 is a multiplier diode, and 11 is a resonant bar. 13 is a feed-through capacitor, 20 is an output circuit (cutoff waveguide), 21 is a waveguide for output extraction, 22 is a Ritz, 25
2 denotes a terminal, and 26 denotes an external waveguide. (10)

Claims (1)

[Claims] 1. An oscillation multiplication type micro that extracts a signal at the Nth harmonic frequency (N is an integer of 2 or more) of the fundamental oscillation frequency generated by this circuit from the output of a microwave oscillator using an oscillation transistor. The wave oscillation device comprises a cut-off waveguide consisting of an output extraction waveguide for extracting the signal of the Nth harmonic frequency and a ridge for matching the Nth harmonic frequency, and D of the oscillation transistor
A microwave oscillation device characterized by comprising means for supplying a C bias through the Litz.