Solid-state Microwave Oscillators Research Articles

Burst Signal Synchronization Characteristics of Solid-State Microwave Oscillators

The problem of direct synchronization of a Solid-state Microwave (SSMW) oscillator in the face of a burst like input signal has been critically examined. Effect of the intune, the off-tune càrrier and the loaded cavity on the system response have been considered. Two methods have been suggested to improve the tracking response of the oscillator.

Use of synchronization methods for measurement of fluctuations in ultralow-noise solid-state microwave oscillators

The amplitude and frequency fluctuations of a synchronized oscillator and the fluctuations of the phase difference between input and output are examined. Synchronization methods are demonstrated for measurement of the frequency fluctuations of ultralow-noise low-power microwave oscillators, for which conventional methods are unsuitable. The methods are verified.

Phase noise reduction of a 19 GHz veractor-tuned Gunn oscillator for electron paramagnetic resonance spectroscopy

Klystrons are being replaced with solid-state microwave oscillators by designers of microwave bridges for electron paramagnetic resonance (EPR) spectroscopy. Veractor-tuned Gunn oscillators have a number of advantages, but phase noise 100 kHz from the carrier is excessive. A Pound-type dc automatic frequency control (AFC) circuit is described that reduces phase noise of a Hughes veractor-tuned 19 GHz Gunn osillator by 23 dB, resulting in a value of −117 dBc/Hz. This value is typical for a good quality external-cavity reflex klystron at this frequency. It is concluded that the oscillator with AFC exhibits sufficiently low phase noise for normal EPR spectroscopy.

Microwave Laboratory Experiments Using Computer-Aided Test

Computer-aided testing can increase the efficiency and accuracy of university laboratory experiments, while also increasing student interest. Examples of computer-aided RF and microwave experiments being used in the Electronics Engineering Technology Program at Brigham Young University are given. The experiments use interactive programming in a scaled down, semi-automated method designed to minimize cost and complexity, while keeping the student involved. Examples include experiments in microwave radiation and propagation, microwave antenna characteristics, and solid-state microwave oscillator characteristics. A student antenna test exercise using computer automated testing is also described. Abbreviated examples of software used in automating the experiments are given.

Varactor diode for tuning high-power solid-state microwave oscillators

A novel varactor diode has been developed for tuning high-power microwave solid-state oscillators. The resulting output power against frequency remains much flatter than conventional high-power varactor-tuned oscillators.

Eigenvalue Spectrum of Rectangular Waveguide with Two Symmetrically Placed Double Ridges

The eigenvalue spectrum of rectangular waveguide with two symmetrically placed double ridges has been determined by formulating an integral eigenvalue problem and solving by Ritz-Galerkin method. The bandwidth characteristic is found to be adequate for varactor-tuned solid-state microwave oscillator applications requiring ridge structure for resonator. There remains some ambiguity in the designation of trough modes.

Stabilization of a solid-state microwave oscillator by cavity coupling

A transferred electron oscillator (TEO) is a non-linear device. Its operation depends on the circuit loading at the fundamental and harmonic frequencies. This paper discusses a method of stabilization of a TEO by coupling an auxiliary cavity to the oscillator and adjusting the same for optimum performance. Added advantages are noise reduction and finer tuning capability. Experimental results and computer analysis are also discussed.

Simple Stabilizing Method for Solid-State Microwave Oscillators (Short Papers)

In the microwave solid-state oscillators using bulk effect and avalanche diodes, high dielectric constant ceramics have been used as a temperature compensator and excellent temperature stability is obtained. An X-band avalanche diode oscillator is tested over a wide temperature range. The frequency drift is improved to be less than +30 kHz//spl deg/C. Additional advantages of this technique are compact size and low cost.

Large signal circuit characterization of solid-state microwave oscillator devices

A method of direct measurement of the admittance in X band seen by an encapsulated solid-state oscillator embedded in microwave hardware is described. It is applicable to many two-terminal devices in waveguide, coaxial line or microstrip circuit configurations. The criterion for oscillation in negative conductance oscillators is used in conjunction with these admittance measurements to determine the complete frequency-dependent 'device-plane' of Gunn and IMPATT devices in S4 (pill-prong) encapsulations, and the forms of negative conductance and susceptance variation with RF voltage amplitude and frequency have been extracted for each of these devices. It is found that for transferred-electron devices in particular, the frequency dependence of these parameters over X band is very marked. The use of the admittance measuring technique to characterize the microwave circuit is discussed with reference to the improvement of AM and FM noise by the controlled insertion of perturbations in the admittance locus, and an example is given of its use in fault-finding in a mechanically tunable waveguide oscillator.

The Concept and Performance of Wideband Solidstate Microwave Oscillator having Automatic Frequency Control

The concepts pertaining to the design of a wideband microwave oscillator using step-recovery diode harmonic generators are given. Two different automatic frequency control and locking networks have been evolved for use in conjunction with this oscillator. The performance of these is described and discussed.

Radar

As the field of radar is very large, the treatment in the paper is necessarily brief, and is mainly confined to techniques and systems of current interest. All radar systems are subject to fundamental performance constraints stemming from the range, range rates and angle-measurement processes which are basic to radar. Most modern radar systems of interest are subject to further constraints arising from the environment in which they operate. The choice of the radiated carrier frequency affects many aspects of radar performance, including aerial directivity, the ability to distinguish target radial velocity, the target echoing area, attenuation in the atmosphere and clutter echoes. Highly directional aerials provide the basis for radar angle measurement and significant recent advances have been made in this field. Transmitters, including high-power transmiters and low-power solid-state microwave oscillators and amplifiers, are discussed. Radar receiving systems have been strongly influenced by recent advances in solid-state technology. Closely associated with the basic receiving function is the signal processing needed to achieve an acceptable approximation to matched filtering of the radar-echo signal. Radar-display technology continues to be dominated by the cathode-ray tube, however, the data presented for display are increasingly subject to preprocessing, often by digital computer, prior to display to the radar user. The use of computers in association with radar, initially to facilitate information display, has been broadened to more fully adaptive systems, in which the operating parameters of the radar are continuously adjusted to match the immediate requirements of the task in the light of information already obtained. By reradiating a pseudoecho on a frequency different from that of the radar, co-operative targets may be detected without any problems of clutter. Such radar operation is termed secondary radar. The paper concludes with brief description of air-surveillance radar, radar in guided weapons, radar in aircraft navigation, radar in airborne air defence, radar on the battlefield, miniature radars, radar meteorology and over-the-horizon radar.

Wide-range tuning of solid-state microwave oscillators

Equations are derived that give the electronic tuning range of solid-state microwave oscillators in terms of the Q factor of the tuning device and the available power output. For currently available varactors the tuning range is severely limited by the Q factor but some exchange of power output for the tuning range is possible. It is shown that series tuning is superior to shunt tuning.

Problems of design and fabrication of a C.W. silicon IMPATT diode

The theory of the IMPATT diode is briefly described and design criteria proposed. The design of a device which is both an efficient microwave oscillator and suitable for batch production involves electrical, mechanical and thermal considerations. These are discussed with reference to the chosen device. The problems affecting overall reliability of constructing this device in large reproducible numbers are then discussed and an optimized process outlined. Evidence is provided in the form of thermal resistance and microwave measurements to show that this process is suitable for the batch production of a useful solid state microwave oscillator.

Effects of changes in operating conditions on the phase of a frequency-locked Gunn oscillator in X band

The frequency and phase-locking properties of solid-state microwave oscillators are of current interest in the contexts of phase control of oscillators, and the combining of a number of oscillators to achieve improved output power. A particular case of interest is that of the phased array antenna, in which the dual functions of power combination and beam steering are needed. In the latter case, it may be necessary to have control over the relative phases of a large number of oscillators locked to a common frequency. In a phased array, there is a special need to set the relative phases of the oscillators accurately, and to maintain the accuracy of the settings as parameters such as ambient temperature vary. A number of workers have investigated the frequency-locking properties of negative-resistance oscillators, but no comprehensive study of their phase-locking properties has been reported.

A.M.- and f.m.-noise characteristics of solid-state microwave oscillators

The a.m.- and f.m.-noise spectra for two different types of X band solid-state signal sources are presented. These measurements were carried out on a specially designed noise-measuring system.

Solid-State Microwave Amplifier and Oscillator Using Ferrite

Solid-State Microwave Amplifier and Oscillator Using Ferrite

A Solid-State Microwave Amplifier and Oscillator Using Ferrites

A Solid-State Microwave Amplifier and Oscillator Using Ferrites