SU1566452A1 - Microwave self-excited oscillator - Google Patents

Abstract

This invention relates to microwave radio engineering. The purpose of the invention is to increase the output power while maintaining a wide tuning band, as well as improving the linearity of the modulation characteristic. The microwave oscillator contains a bipolar transistor 1, segments 2, 11-13 of the microstrip line, chokes 3, 5 14, capacitors 4, 7, 10, 16, resistors 6, 15 and varicaps 8, 9. The increase in output power is due to incomplete including varicaps 8, 9 in the oscillating circuit through the capacitor 10, as a result of which the losses in this circuit decrease and its Q-factor increases. When the conditions of phase and amplitude balance are satisfied, auto-oscillations are excited in the circuit, the frequency of which is determined by the length of section 11. The frequency tuning range is determined by the range of variation of the control voltage. In order to improve the linearity of the modulation characteristic, segment 13 is introduced. An adjustable two-terminal circuit, formed by the parallel connection of varicaps 8, 9 and open segment 13, has a linear dependence of conductivity on frequency. A linear change in the frequency of the oscillator is provided when the conductivity of the two-pole is changed from a change in the control voltage. 1 il.

Description

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The invention relates to microwave radio technology, in particular to frequency modulated microwave oscillators, and can be used as a signal source for FM radio transmitting equipment systems with increased requirements for frequency tuning linearity.

The purpose of the invention is to expand the scope by increasing the output power while maintaining a wide tuning bandwidth, as well as improving the linearity of the modulation characteristic.

The drawing shows a circuit diagram of the microwave autogenous oscillator.

Microwave aBToreHepatop contains a bipolar transistor 1, the base of which is connected to a common bus, the emitter is connected to one end of the first segment 2 of the microstrip line, the collector to one end of the first droplet 3, the other end of which is connected to the positive pole of the power source and through the first capacitor 4 A common choke 5 connected to one end of the first resistor 6, the second end of which is connected to the source of control voltage, with a common point of the second throttle 5 and the first resistor 6 on the second capacitor 7 with a common bus; the second end of the second throttle 5 is connected to the cathodes of the first 8 and second 9 varicaps and one lining of the third capacitor 10, the second lining of which is connected to the junction point of the second 11 and third 12 microstrip line; the second segment 11 of the microstrip line is connected to the collector of the bipolar transistor 1 and one end of the first throttle 3, and the other end of the third segment 12 of the microstrip line is the output of the microwave oscillator, the fourth segment 13 a strip line, one end of which is open and the other connected to the connection point of one end of the second throttle 5 with one lining of the third capacitor 10, with the cathodes of the first 8 and second 9 varicaps, the third choke 14, one end of which is connected to the other end of the first segment 2 micro0

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the strip line and the other through the second resistor 15 with the negative pole of the power source, and the connection point of the third drossel 14 and the second resistor 15 is connected via a fourth capacitor 16 to a common bus.

Microwave oscillator works as follows.

A microwave oscillator, made on a bipolar transistor 1 according to the common base scheme, is a capacitive three-point, in which the oscillating circuit is parallel, and the inductive branch of the oscillating circuit forms a 11 microstrip line with incompletely included varicaps 8 and 9, and the capacitive one the branch of the parallel circuit forms the collector junction capacitance — the base of the bipolar transistor 1. The control voltage to varicaps 8 and 9 is supplied from the control voltage source through the first resistor 6 and the second dross Spruce 5, made in the form of a quarter-wave segment of a high impedance microstrip line, is blocked by the second capacitor 7. The first resistor 6 serves to limit the current through the varicaps 8 and 9.

The supply voltage to the emitter and collector of the bipolar transistor 1 is made through the third 14 and first 3 chokes, respectively, necessary for uncoupling the power supply at high frequency and made in the form of quarter-wave sections of high-resistance microstrip line, blocked by the fourth and first capacitors 16 and 4, respectively .

An increase in the power of the microwave auto-generator is achieved due to the incomplete connection of the varicaps 8 and 9 into the oscillatory circuit through the third capacitor 10, as a result of which the losses in the oscillating circuit decrease, and its Q-factor increases. When the conditions of phase and amplitude balance are satisfied, auto-oscillations are excited in the circuit, whose frequency is determined by the length of the second segment 11 of the microstrip line. The frequency tuning range is determined by the variation range of the control voltage. To improve the linearity of the modulation characteristic of the microwave oscillator, an open-ended section is used.

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13 microstrip lines. An adjustable two-terminal network formed by parallel connection of the varicaps 8 and 9 and the open-ended segment 13 of the micro-strip line has a linear dependence of conductivity on frequency, i.e. provides a linear change in the frequency of the microwave oscillator when the conductivity of the two-pole is changed from a change in the control voltage,

Claims (2)

1.AHF oscillator containing a bipolar transistor, the base of which is connected to a common bus, the emitter is connected to one end of the first microstrip line, a collector from one end of the first throttle, the other end of which is connected to the positive pole of the power source and through the first capacitor a common bus, the second choke, one end connected to one output of the first resistor, the second output of which is connected to the source of control voltage, and the connection point of the second throttle and the first resistor is connected Nena through the second capacitor to the common bus, the second end of the second inductor connected to the cathode of the varicap and one plate of a third capacitor, a second resistor and a fourth capacitor, wherein 5664526 By the fact that, in order to increase the output power while maintaining a wide tuning band, the second and third segments of the microstrip line, the third choke and the second varicap are introduced into it, while the second varicap is connected in parallel to the first varicap, the third choke is connected by one end. to the other end of the first segment of the microstrip line, and the other end through the second resistor is connected to the negative pole of the power source and through the fourth capacitor to the 15 common bus, the second and tritium sections of the microstrip line are connected one end and the third capacitor is connected to the point of their connection by another plate, another cat-c of the second microstrip line is connected to the collector bipolar transistor connection point with the first inductor, and the other end of the third microstrip line is $ 1 C output of the auto-oscillator , 2. The microwave oscillator according to claim 1, characterized in that, in order to improve the linearity of the modulation characteristic, a fourth section of the microstrip line is introduced, open at one end, the other end of which is connected to the junction of the varicap cathodes, the third capacitor and the first throttle. 20