Broad-Band Varactor-Tuned Impatt-Diode Oscillator (Short Papers)

A varactor-tuned IMPATT-diode oscillator with a continuous and monotonic tuning bandwidth of 27 percent and a potential tuning range in excess of 40 percent is described. The results of a computer program which optimizes the tuning bandwidth of the equivalent circuit of the voltage-controlled oscillator (VCO) are presented. The VCO consists of two varactors located symmetrically on each side of an IMPATT diode all mounted in a ridged waveguide with two matched outputs into 50-Omega coaxial. Experimental results on bandwidth, power output, frequency linearity, and FM noise are presented.     

A Discriminator-Stabilized Microstrip Oscillator (Short Papers)

A 5.2-GHz microstrip Gunn oscillator has been frequency stabilized by means of a novel microstrip discriminator and integrated feedback loop. A stabilization factor of 1000 was measured for the oscillator with art external Q of 50. The self-capture bandwidth of the discriminator circuit is large enough to eliminate the need for a search voltage to obtain initial frequency locking.     

Q-dependence of Gunn Oscillator FM Noise (Short Papers)

Measurements of FM noise and the external quality factor Q/sub ex/ of X-band Gunn oscillators are reported which show that both unconverted and intrinsic FM noise vary inversely as Q/sub ex/, if bias voltage, RF power, and frequency are kept constant.     

A Magnetically Tunable Microstrip IMPATT Oscillator (Short Papers)

Magnetically tunable resonators have been constructed in microstrip on a ferrite substrate. A large tuning range is obtained with an external magnetic field applied in the direction of the RF propagation, 17 MHz/Oe for magnetic fields from 0 to 30 Oe. A variable frequency microstrip oscillator which uses this effect is described; measurements made on an X-band IMPATT oscillator illustrate a tuning range from 9.4 to 10.5 GHz with an output power of 330 mW /spl plusmn/ 0.5 dB.     

Temperature Stability of an MIC Gunn-Effect Oscillator (Short Papers)

A technique to temperature stabilize a Gunn-effect CW oscillator (C band) in microstrip, has been developed.     

A Stabilized MIC Oscillator Using a Germanium Avalanche Diode (Short Papers)

A stabilized X-band oscillator using a germanium avalanche diode in a microwave integrated circuit (MIC) is proposed. The stabilization is achieved by coupling a transmission cavity to the resonant cavity in which an avalanche diode is embedded. A mode-jumping problem inherent in a coupled-cavity oscillator was solved coupling a third varactor-embedded low-Q cavity to the transmission cavity. As a result, single-mode oscillation in an MIC oscillater was successfully obtained. Varactor tuning can also be realized with as small a change in output power as 7 percent for a tuning range of 30 MHz. The experimental results and the theoretical analysis of the new stabilized oscillator are given.     

Microwave Oscillator Noise Measuring System Employing a YIG Discriminator (Short Papers)

A microwave oscillator noise measuring system employing a YIG discriminator has been developed. The resonant frequency of the YIG discriminator is automatically tuned to follow the drift of the carrier frequency of the oscillator under test. This arrangement permits an accurate measurement of FM noise spectra near the carrier frequency as close as several tens of Hz off the carrier. The drift of the carrier frequency is measured over a wide range by monitoring fluctuations of the feedback current in the compensation coil that supports a part of the biasing magnetic field for the YIG discriminator.     

The Ridged-Waveguide-Cavity Gunn Oscillator for Wide-Band Tuning (Short Papers)

A method of construction of the Gunn oscillator for wideband frequency tuning has been developed using the ridged-waveguide cavity. The ridged waveguide can be designed to provide the dominant mode with a wide bandwidth, and also to provide the higher order cutoff modes whose resonance is a limiting factor of the tuning range for oscillators of conventional design with reduced stored energies to permit wide-band tuning. A prototype oscillator having a packaged X-band diode demonstrated an 8-18-GHz tuning range.     

A Single-Tuned Oscillator Circuit for Gunn Diode Characterizations (Short Papers)

A Gunn diode oscillator circuit with predictable performance has been developed based on a concept already shown to be practical with IMPATT diodes. Frequency jumps, multifrequency output, and tuning difficulties are eliminated without sacrificing circuit efficiency. The circuit is quite versatile and well suited for Gunn diode characterizations.     

Electronic Tuning of the Punch-Through Injection Transit-Time (PITT) Microwave Oscillator (Short Papers)

Experimental results of the dynamic resistance and capacitance of p+-n-p+ punch-through injection transit-time (PITT or BARRITT) diodes are presented. A method of predicting the oscillator electronic tuning from the change in the device capacitance is outlined and verified experimentally at X band.     

A Technique for Determining the Local Oscillator Waveforms in a Microwave Mixer (Short Papers)

A technique is described which enables the large-signal current and voltage waveforms to be determined for a mixer diode. This technique is applicable to any configuration where the impedance seen by the diode at the local oscillator (LO) frequency and its harmonics is known.     

Active Stabilization of Crystal Oscillator FM Noise at UHF Using a Dielectric Resonator (Short Papers)

A low-noise 600-MHz crystal oscillator circuit is described. It uses a dielectric oscillator as the dispersive element of a discriminator in an active frequency stabilization loop which reduces the near-carrier FM noise. The innovation in the circuit is an essentially noiseless active carrier suppression loop, which allows maximum utilization of a low-noise RF amplifier to reduce the discriminator threshold (Delta f/sub rms/) to 2.5x10-5 Hz in a 1-Hz bandwidth. The FM noise 1 kHz from the carrier was reduced by 44 dB to this threshold, equivalent to a phase-noise spectral density of -152 dBc/Hz.     

A New Two-Three-Phase Voltage-Controlled Oscillator

The initial aim of the work has been the development of an inexpensive quadrature oscillator which can operate as a rapidly responding voltage-controlled oscillator (VCO) in two phases. Such rapid operation in quadrature is needed in association with quickly operating phase-locked loops for frequency synthesizers and similar applications. Other applications, where the relatively large speed is not essential, but where the phase shifts between various outputs should be precise, are mentioned in concluding this section. The electronic realization is made relatively cheap by proposing a replacement of the instantaneous amplitude measuring operation of square and sum (x2 + y2) (associated in the process of amplitude stabilization) by an operation of three-phase rectification. This leads to the construction of a versatile instrument which generates three-phase signals as well as two-phase signals (the two-phase signals are both sinewaves in quadrature and also square waves in quadrature). All these waveforms are capable of participating in the system performance as a VCO at a relatively large rate of frequency changes. A reversal in the order of phases when the frequency-control voltage crosses zero is also exhibited. This is needed in applications in industrial and power electronics. Our main aim now is to use the instrument in association with a precisely stabilized quickly responding cyclo-converter. Other possible applications of the instrument are in the field of precise measurements (for example, in the detection of signals by lock-in amplification there exists a frequent need for quadrature operation) and in telecommunication.     

X波段微带集成FET的压控振荡器

本文叙述了一种利用FET振荡管和GaAs超突变结变容二极管构成的电压控制振荡器(VCO).通过合理的电抗补偿和阻抗匹配技术的应用,VCO在8GHz得到调谐带宽1200MHz,输出功率大于20mW.     

Measurement of the Electromagnetic-Field Components in a Rectangular Drift Tube-Loaded Cavity Using Various Perturbing Objects (Short Papers)

The electric-field quantities E, E/sub y/, E/sub z/, and the magnetic-field quantities H and H/sub x/ in a rectangular drift tube-loaded cavity resonating in the TE/sub 101/ mode have been measured along the z direction by means of the perturbation method using a dielectric bead, a metallic disk, a metallic needle, a metallic sphere, and a ferrite disk. The relative errors for E and E/sub y/ are 3 percent; for E/sub z/, 10 percent on the average; whereas for H and H/sub z/, they are 10 percent at least. The ferrite disk, being superior to the metallic sphere, offers a new technique in determining magnetic-field components in cavity resonators.     

Ka-Band FET Oscillator (Short Paper)

The design and performance of GaAs FET oscillators operating near 36 GHz are presented. The oscillators used readily available GaAs FET's and were built in a microstrip circuit configuration. An output power of about +8 dBm was obtained with two devices in a single oscillator.     

Slot-Line Transitions (Short Papers)

Coax-slot and microstrip-slot transitions are discussed. Experimental VSWR and impedance data are presented and compared with values computed using equivalent circuits for these transitions. Thick-film chip terminations are also investigated.     

An Accurate 1.08GHz CMOS LC Voltage-Controlled Oscillator

An accurate 1.08GHz CMOS LC voltage-controlled oscillator is implemented in a 0.35μm standard 2P4M CMOS process.A new convenient method of calculating oscillator period is presented.With this period calculation technique,the frequency tuning curves agree well with the experiment.At a 3.3V supply,the LC.VCO measures a phase noise of －82.2dBc/Hz at a 10kHz frequency offset while dissipating 3.1mA current.The chip size is 0.86mm×0.82mm.     

Characterization of Microwave Oscillator and Amplifier Circuits Using an IMPATT Diode Biased Below Breakdown (Short Papers)

A convenient laboratory technique is described to measure the internal circuit loss, the load conductance, and equivalent circuit susceptances of microwave diode oscillators and amplifiers using an IMPATT diode biased just below its breakdown voltage.