Band Gunn Oscillator Research Articles

The impact of resonator detuning on autodyne characteristics of stabilized microwave generators

Results of investigations of autodyne characteristics of microwave generators stabilized by an external high-Q resonator as a function of the oscillations frequency detuning and the natural frequency of the stabilizing resonator have been presented. Main mathematical expressions describing the autodyne response of generator to the impact of intrinsic radiation reflected from target were obtained. The design of the coupling between the main working and stabilizing resonators was implemented by using a circuit of band-reflecting filter with resistive coupling. The calculations of amplitude, frequency, and amplitude-frequency characteristics of the autodyne system were carried out under various conditions. The experimental data qualitatively corroborating the inferences of theoretical studies were obtained by investigating the case of a hybrid-integral 8-mm band Gunn oscillator.

Phase and Amplitude Drift Research of Millimeter Wave Band Local Oscillator System

In this paper, we developed a local oscillator (LO) system of millimeter wave band receiver for radio astronomy observation. We measured the phase and amplitude drift stability of this LO system. The voltage control oscillator (VCO) of this LO system use the 3 mm band Gunn oscillator. We developed the digital phase locked loop (DPLL) module for the LO PLL function that can be computer-controlled. To verify the performance, we measured the output frequency/power and the phase/amplitude drift stability of the developed module and the commercial PLL module, respectively. We show the good performance of the LO system based on the developed PLL module from the measured data analysis. The test results and discussion will be useful tutorial reference to design the LO system for very long baseline interferometry (VLBI) receiver and single dish radio astronomy receiver at the 3 mm frequency band.

Thermistor controlled gunn oscillator at Ka-band

Frequency drift of Gunn oscillators is a major cause of concern in most of the Millimeter wave communication systems. This paper describes a simple and cost effective technique to arrest the frequency drift of a Ka band Gunn oscillator within 15 MHz for the operating temperature range of 0°C to 60°C as against a typical drift of about 50 to 100 MHz for free running Gunn oscillator for the same temperature range. At the ambient, the oscillator remains within ±1 MHz from switching on to stabilization. The temperature variation is sensed with a small thermistor bead placed close to the diode and a correction voltage is applied to the bias to compensate for the frequency drift. This compensation circuit also takes into account the non-linear behaviour of the thermistor and the Gunn oscillator with the temperature.

A Highly Stabilized K/sub a/-Band Gunn Oscillator (Correspondence)

The construction and experimental results of a highly stabilized K/sub a/-band Gunn oscillator are described. The frequency stability is 3x10/sup -5/ at 25 GHz over the temperature range from 0 to 50/spl deg/C. An output power of more than 20 mW has been obtained in the frequency range up to 30 GHz. The frequency-saturation effect is also described.

1/4 W continuous-wave Q band Gunn oscillator

C.W. Gunn devices using integral-heatsink techniques have been produced with a power output of more than ¼ W at 31.5 GHz. Conversion efficiencies of up to 4.6% are reported. A tuning range greater than 8 GHz has been obtained.

Relationship of the starting delay time and frequency/temperature characteristics of X band Gunn oscillators

The temperature variation of the frequency of c.w. X band Gunn oscillators is shown to be related to the temperature variation of the starting delay time of the diode used as a pulsed oscillator. The results suggest that contact resistance acts as a passive circuit element to increase the growth time constant.

Broadband (1.95 GHz) varactor tuned X band Gunn oscillator

Gunn devices mounted in an X band-waveguide cavity have been varactor-tuned over 1.95 GHz and mechanically tuned over 3.0 GHz. The minimum output power over this range was 14 mW and the temperature stability 150 kHz/degC.

High-speed phase and amplitude modulation of Gunn oscillators

Linear phase and amplitude modulation of X band Gunn oscillators up to 3 GHz modulating rates has been observed. The modulating signal was applied through the bias circuit, and typical sensitivities were 0.1 rad/V and 10% depth of modulation/volt, respectively. A simple theoretical explanation of the results is given.

X band Gunn oscillators triggered by baseband Gunn diodes

A 155 μm-long Gunn diode produces output pulses of 1.5 V amplitude in resistive loading. These pulses are used to trigger a transistor multivibrator and an X band Gunn oscillator.

Signal-injection triggering of X band Gunn oscillators for f.s.k. operation

Experimental results show that the threshold effects of signal-injection triggering of Gunn oscillators can be employed for binary frequency-shift-keyed regenerator operation.

Theoretical study of the effect of temperature on X band Gunn oscillators

The output power of X band gallium-arsenide oscillators has been calculated numerically as a function of temperature and bias voltage. Results are presented and compared with experimental data obtained previously. The existence of a hybrid of the domain and l.s.a. modes of operation is predicted.

Microwave Gunn oscillator tuned electronically over 1 GHz

A J band Gunn oscillator, tuned by a varactor, has been constructed. It can be mechanically tuned over 3 GHz, and an electronic tuning range of 1 GHz has been achieved with an average power output of 15 mW and less than 1 dB variation.

Frequency-modulation noise in Gunn oscillators

The frequency-modulation noise in X band Gunn oscillators has been measured. The overall spectral width is determined by low-rate (<1Hz) fluctuations with an r.m.s. value in the region of 3kHz.

Miniature X band Gunn oscillator with a dielectric-tuning system

An X band Gunn oscillator weighing 1¼oz is described. Its dielectric-tuning system can be readily designed to give any required mechanical tuning range up to about 2 GHz, and it can be electronically tuned over about 70 MHz with a low-cost varactor. The theory of the dielectric tuning system is presented.