JPS5930309A - Voltage tuning microwave semiconductor oscillator - Google Patents

Abstract

PURPOSE:To adjust an oscillating frequency, by connecting a frequency adjusting electrode made of a metallic piece to other end of a 1/4 wavelength transmission line short-circuiting a varactor diode in terms of high frequency. CONSTITUTION:The oscillating frequency of a GaAs meta semiconductor FET3 depends mainly on a junction capacitance of the varactor diode 7 and the length lg of a gate electrode transmission line 2 constituting a resonance circuit. Further, the frequency at which the diode 7 is short-circuited in terms of high frequency is changed by connecting the metallic piece of the frequency adjusting electrode 9 to an end of the 1/4 wavelength transmission line 8 short-circuiting the diode 7 in terms of high frequency by means of a jumper 10. That is, the adjustment of the oscillating frequency is attained by connecting the line 8 and the metallic piece of the electrode 9 with the jumper 10 for a suitable number.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voltage-tunable microwave semiconductor oscillator that is incorporated in a microwave integrated circuit board (hereinafter referred to as an MIC board) and whose oscillation frequency can be tuned by a bias voltage of a varactor diode.

FIG. 1 is a plan view showing a conventional voltage-tuned microwave semiconductor oscillator. In the figure, (1) is made of ceramics or Teflon (Teflon), which have low dielectric loss in the microwave band.
M consisting of eflon (product name of DuPont, USA), etc.
A dielectric substrate as an IC substrate, (2) is a gate electrode transmission line, (3) is a drain electrode transmission line, (4) is an output matching line, (5) is a 50Ω output line, and (6) is a gate electrode (6). ) is connected to the gate electrode transmission line (2), the drain electrode (b) is connected to the drain electrode transmission line (3), and the source electrode (S) is connected to the output matching line (4). Gallium arsenide metal semiconductor field effect transistor (hereinafter GaAmME) as an element
8FET), (7) is a varactor diode whose junction capacitance changes depending on the bias voltage, and (8) is a 1/4 of the varactor diode that short-circuits this varactor diode (7) at high frequency.
It is a wavelength transmission line.

In addition, the gate electrode transmission line (2), the drain electrode transmission line (3), the output matching line (41, 500 output line (
5) and the 1/4 wavelength transmission line (8) are microstrip lines formed by photoetching a multilayer metal film of chromium and gold formed by vapor deposition or plating.

Next, the operation of the voltage-tuned microwave semiconductor oscillator with the above configuration will be explained. First, GaAs MESFET
(of the drain electrode 61) is connected to the 1/4 wavelength drain electrode transmission line (3), so it is in a short-circuited state in terms of high frequency. Generally, GaAs MESFET f61 that operates in the microwave band has a drain electrode (9).
When short-circuited, it becomes unstable at high frequencies.

Therefore, the GaAs MESFET is unstable at high frequencies.
Gate electrode transmission line (2) to gate electrode (G) of (6)
and a resonant circuit composed of a varactor diode (7), and connect a 500Ω output line (5) with the same characteristic impedance as the 50Ω load normally used in the microwave band and a source electrode (S) to an output matching line ( By matching in step 4), microwaves can be oscillated.

Note that the oscillation frequency of this voltage-tuned microwave semiconductor oscillator is mainly determined by the gate electrode transmission line (length tg of 2+ and the junction capacitance of the varactor diode (7) that constitutes the resonant circuit, so the voltage tuning of the oscillation frequency is The junction capacitance of the varactor diode (7) can be changed by changing the bias voltage.

In this way, since the conventional voltage-tuned microwave semiconductor oscillator is made into an MIC, (a) the oscillator is easy to design, (b) it is small and lightweight, and (c) it has a small number of parts. It has advantages such as easy assembly and high reliability.

However, since conventional voltage-tuned microwave semiconductor oscillators do not have a part to adjust the oscillation frequency, (e) the length of the gold wire used for bonding the varactor diode (7), the junction capacitance of the varactor diode (7), The oscillation frequency will vary due to manufacturing variations such as the length tg of the gate electrode transmission line (2).When making voltage-tuned microwave semiconductor oscillators with different oscillation frequencies, it is necessary to adapt the oscillation frequency to each one. Thus, the gate electrode transmission line (2) requires varactor diodes (7) with different lengths tg, which has the disadvantage of increasing manufacturing cost.

Therefore, an object of the present invention is to provide a voltage-tunable microwave semiconductor oscillator whose oscillation frequency can be adjusted.

In order to achieve such an object, the present invention electrically connects a frequency adjustment electrode made of at least one metal piece to the other end of a quarter wavelength transmission line that short-circuits the varactor diodes at high frequency. This will be explained in detail below using examples.

FIG. 2 is a plan view showing an embodiment of the voltage-tuned microwave semiconductor oscillator according to the present invention. In the same figure, (9
) is a frequency adjustment electrode made of a plurality of metal pieces placed at the end of the 1/4 wavelength transmission line (8), and 00) is a frequency adjustment electrode (00) between the 1/4 wavelength transmission line (8) and this frequency adjustment electrode (00).
9) A connecting wire such as a gold wire that electrically connects the metal pieces.

Next, the operation of the voltage-tuned microwave semiconductor oscillator with the above configuration will be explained. First, GaA5ME 5FE
Since the drain electrode (to) of T (61) is connected to the drain electrode transmission line (3) of 14 wavelengths, it is in a short-circuited state in terms of high frequency. 6J is unstable at high frequencies when the drain electrode (b) is short-circuited.For this reason, this GaAs MESFET is unstable at high frequencies.
(Gate electrode transmission line (2) to gate electrode (G) of 61)
and a resonant circuit composed of a varactor diode (7), and connect a 500Ω output line (5) with the same characteristic impedance as the 50Ω load normally used in the microwave band and a source electrode (S) to an output matching line ( By matching in step 4), microwaves can be oscillated.

The oscillation frequency is determined by the length tg of the gate electrode transmission line (2) that constitutes the resonant circuit and the junction capacitance of the varactor diode (7J), so the voltage tuning of the oscillation frequency is achieved by changing the bias voltage. The junction capacitance of (7) can be changed.Furthermore, a frequency adjustment electrode (9) is installed at the end of the quarter wavelength transmission line (8) which short-circuits this varactor diode (7) at high frequency. When the metal pieces are connected with the connection line Ql, the frequency at which the varactor diode (7) is shorted in high frequency changes.Therefore, the oscillation frequency also changes.
The oscillation frequency can be adjusted by connecting an appropriate number of metal pieces of the 1/4 wavelength transmission line (8) and the frequency adjustment electrode (9) with the connecting wire 00).

Figure 3 is a diagram showing the measurement results of the frequency adjustment characteristics of the voltage-tuned microwave semiconductor oscillator shown in Figure 2, where the horizontal axis is 1
/4 Frequency adjustment electrode (9) connected to the wavelength transmission line
) represents the number N of metal pieces, and the vertical axis represents the oscillation frequency f and the oscillation output P. In addition, the GaAm MESFET used
f61 has a gate length of 1 μm, a gate width of SOO μm, and a saturated drain current of 180 mA. The GaA3 Schottky barrier diode (7) has a junction diameter of 10 μm and a junction capacitance at IV reverse bias of 2.5 PF.

The 1/4 wavelength transmission line (8) is a microstrip line with a length of 2.9 mm and a characteristic impedance of 50 Ω. The frequency adjustment electrode (9) is a metal piece of 0.2 x 0.2
Arrange 4 pieces at intervals of yattt. Also, GaAgMESF
ET (source electrode (S) of 6J and gate electrode 1) and 5
A resistor Rs of 0 is connected, a bias voltage VB of 6 and a bias current 1 of 140 mA are applied between the drain electrode (b) and the gate electrode, and a varactor bias voltage of 12 V is applied to the GaAa Schottky barrier diode. Apply 7.

As shown in Fig. 3, the 1/4 wavelength transmission line (8
), the oscillation frequency f can be adjusted from 8.5 GHz to 9.1 GHz while maintaining the oscillation output P at 100 mW or more. Further, when the varactor bias voltage (7) is changed from -5V to -12V, a voltage tuning width of about 200MHz is obtained.

Further, although the above embodiment shows a case where a GaAs MESFET is used as the three-terminal microwave semiconductor element, it goes without saying that a microwave junction type transistor may also be used. Further, although a case is shown in which a gold wire is used as the connection line 00), it goes without saying that a gold ribbon may also be used.

As explained in detail above, according to the voltage-tuned microwave semiconductor oscillator according to the present invention, a resonant circuit is connected to one electrode of the three-terminal microwave semiconductor element that is incorporated on the MIC substrate and is unstable at high frequencies. At the other end of the 1/4 wavelength transmission line, which connects the transmission line and the varactor diode that make up the transmission line and short-circuits the varactor diode at high frequency, there is a frequency adjustment material made of multiple metal pieces that can be connected to this transmission line. The arrangement of the electrodes has the effect of making it possible to adjust the oscillation frequency.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a conventional voltage-tuned microwave semiconductor oscillator, FIG. 2 is a plan view showing an embodiment of the voltage-tuned microwave semiconductor oscillator according to the present invention, and FIG. 3 is a plan view showing the voltages shown in FIG. FIG. 3 is a diagram showing measurement results of frequency adjustment characteristics of a tuned microwave semiconductor oscillator. (1) Dielectric substrate (microwave integrated circuit), (
2)...Gate electrode transmission line, (3)...Drain electrode transmission line, (4)...Output matching line, (5
)...50Ω output line, (6)...Gallium arsenide metal semiconductor field effect transistor (3-terminal microwave semiconductor device), (7)...Varactor diode, (8)...1 /4 wavelength transmission line (transmission line for high frequency short termination), (91...frequency adjustment electrode, 0
0)... Connection line. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Makoto Kuzuno - Figure 1 1 Figure 2 Figure 3 1234 □N Procedural amendment (voluntary) Commissioner of the Japan Patent Office 1, Indication of case Patent application No. 57-140868 2, Title of invention Voltage-tuned microwave Semiconductor oscillator 3, relationship with the amended person case Patent applicant address 2-3 Sanno-chome, Maruno, Chiyoda-ku, Tokyo Name (601) Mitsubishi Electric Corporation Representative Katayuni Hachibe 4, Agent address 42-5, Sanno-chome 2-3, Maruno, Chiyoda-ku, Tokyo, Column 6 of the detailed explanation of the invention in the specification subject to the amendment, "Can be done" on page 4, line 3 of the specification of the contents of the amendment. "You can do it." I corrected him. Above (2)

Claims (1)

[Claims] A three-terminal microwave semiconductor element that is incorporated on a microwave integrated circuit board and is unstable at high frequencies;
A transmission line connected to one terminal of the terminal microwave semiconductor element, a varactor diode connected to the other end of this transmission line and forming a resonant circuit together with this transmission line to perform voltage tuning of the oscillation frequency, and a varactor diode at one end. a high-frequency short-circuiting transmission line having a length of about 174 wavelengths connected to the other end; and a frequency adjustment electrode made of at least one metal piece electrically connected to the high-frequency transmission line to adjust the oscillation frequency. A voltage-tuned microwave semiconductor oscillator characterized by comprising: