IMPATT Diode Oscillators Research Articles

The Noise Generation in One-Frequency IMPATT Diode Oscillator of Millimeter Wave Range on the Effect of Low-Frequency Harmonic Oscillation

The investigation of effect of the low-frequency harmonic oscillation on the nourishment circuit of the 7 mm wave region IMPATT diode oscillator was continued. In first time it was shown, that excitement of noise and the maximum height-frequency noise spectrum extension at a low-frequency oscillation amplitude increasing are connected with a transitory decreasing of the diode current lower the start current of height-frequency generation in the IMPATT diode oscillator. Keywords: effect, low-frequency harmonic oscillation, IMPATT diode oscillator, 7mm wave range, spectrum, amplitude detector.

Генерация шума в одночастотном генераторе на лавинно-пролетном диоде миллиметрового диапазона длин волн под воздействием низкочастотного гармонического колебания

The investigation of effect of the low-frequency harmonic oscillation on the nourishment circuit of the 7mm wave region IMPATT diode oscillator was continued. In first time it was shown, that excitement of noise and the maximum height-frequency noise spectrum extension at a low-frequency oscillation amplitude increasing are connected with a transitory decreasing of the diode current lower the start current of height-frequency generation in the IMPATT diode oscillator.

Demonstration of IMPATT Diode Oscillators in 4H-SiC

Demonstration of IMPATT Diode Oscillators in 4H-SiC

GaAs W-band impatt diodes for very low-noise oscillators

W-band single-drift flat-profile impatt diodes were fabricated from GaAs MBE material and tested in a full-height waveguide resonant cavity with resonant cap. A quasi-optical parabolic Fabry–Perot resonator was used to determine the FM noise of the GaAs impatt oscillator. With a minimum noise measure of 20 dB at power levels around 20 mW, impatt diode oscillators can compete well with oscillators using Gunn devices. The (N/C)FM = − 82dBc measured at 100 kHz frequency off-carrier and datQex = 95 is comparable to the value obtained from Gunn devices. The maximum available output power of 270 mW, however, markedly exceeds that of Gunn oscillators.

Subharmonic injection locking phenomena in synchronous oscillators

Subharmonic locking behaviour of a synchronous oscillator has been demonstrated. It is shown that the oscillator can be locked using all subharmonics down to the tenth. Locking behaviour is similar to that observed for IMPATT diode and Gunn microwave injection locked oscillators.

A new possibility of detecting lightwave signals through IMPATT oscillators

A novel, yet simple, scheme for detecting intensity-modulated lightwave signals in subcarrier multiplex systems with the help of IMPATT diode oscillators is proposed. The discriminator is seen to exhibit fairly linear characteristics over a moderate band of frequencies. A method of extending the bandwidth without sacrificing the linearity of the system is also suggested. The basic parameters of the system agree closely with the available experimental results. >

Computer-aided analysis of double drift region impatt diode

The results calculated by computer for the double drift region IMPATT diode oscillator on the 8 mm waveband are reported in this paper. A comparison between single and double drift devices concerning the power output and efficiency is given. The effect of doping profile, current density and RF voltage on the performances of these devices have also been investigated. The theoretical data of these double drift IMPATT oscillator and amplifier are provided.

Noise in an IMPATT diode oscillator with second harmonic signals

AbstractMultifrequency operation of IMPATT diode oscillators is important for the improvement of the oscillation efficiency of fundamental signals and for the extraction of higher‐order harmonics.This paper proposes a method to analyze the noise characteristics of IMPATT diodes in multifrequency operations with higher‐order harmonics, and shows the calculation results.In the analysis, a Read diode model is assumed first and the diode noise is analyzed for fundamental and second harmonic operations. Then numerical calculations are carried out to show the characteristics of the noise generated in the diode as AM and FM oscillator noise. In this numerical calculation, AM and FM noises are represented, respectively, as an N/C ratio and as a frequency fluctuation, and their variations with the amplitude and phase relation of the electric field for fundamental and second harmonic signals. Furthermore, the dependences of output power and external Q value of the oscillator on the phase of fundamental and second harmonic signals are also shown, and the optimum phase relation is described.

Low-noise D-band IMPATT oscillators

The single-sideband FM noise characteristics of IMPATT diode oscillators for D-band frequencies have been measured by means of a direct-detection system with a high-Q quasi-optical resonator. For an n-type silicon single-drift IMPATT diode a Δfrms of 11 Hz/√Hz and a noise measure of 37 dB at 137.5 GHz and 26 mW output power was determined.

Mode Jumping and Phase Locking in Impatt Oscillators

The effect of package parasitics on the behaviour of an IMPATT diode oscillator whether it is in a free-running or in injection-synchronized state is studied in detail. Appearance of mode jumping phenomenon in such oscillators, hitherto unknown, has been critically examined and how to get rid of this phenomenon has been predicted. Computer simulation results have been presented to corroborate the theoretical findings.

Nonlinear modelling applied to one-port microwave active circuits

A recently developed nonlinear model for characterising two-terminal microwave active circuits under dynamic and steady-state conditions has been reduced to a form suitable for numerical calculations. The simplified model retains the nonlinear dependence of the active-device currents on RF voltage and frequency and it also takes into consideration the nonlinearity in frequency of the passive circuit. The model is applied to two hypothetically postulated Impatt-diode oscillators and dynamic solutions are calculated. Furthermore the calculated transients are compared with those obtained for a practical oscillator.

Effect of oscillation amplitude on noise in gallium arsenide impatt diode oscillators with uniform doping profile

Effect of oscillation amplitude on noise in gallium arsenide impatt diode oscillators with uniform doping profile

Self-excited oscillations in supply circuit of impatt-diode oscillator

Self-excited oscillations in supply circuit of impatt-diode oscillator

Cavity stabilised Impatt oscillator for ESR spectroscopy

The use of cavity stabilised Impatt diode oscillators for ESR spectroscopy is discussed in different experimental conditions: i.e. as microwave sources in reflection cavity homodyne spectrometers, and as marginal oscillators in which the oscillator cavity (a TE011 cylindrical cavity) is the observing cavity. The sensitivity of this second configuration has been theoretically evaluated for the case in which the Impatt itself is used as a detecting element and in which an external detector is used. For each situation the sensitivity has been measured with a DPPH sample at various power levels giving a sensitivity which is comparable with the best commercial units.

MIC IMPATT diode oscillator stabilised by temperature compensated dielectric resonator

Barium nonatitanate resonators offer simple microwave circuit designs for stabilised oscillators. An integrated circuit X-band IMPATT diode oscillator was designed and results are presented for both the stabilised and unstabilised oscillator. There was a considerable improvement in the stabilised oscillator spectrum and temperature sensitivity, e.g. the unstabilised oscillator had a line width of 0.5 MHz at 38 dB below the peak whereas the stabilised oscillator had a 0.5 MHz linewidth at 52 dB below the peak. The temperature sensitivity of the stabilised oscillator was ~40 kHz/°C over the range 0 to 60°C, which was about a third of that of the unstabilised oscillator.

Microstrip IMPATT-diode oscillator for 100 GHz

The design and performance of a rugged duroid-microstrip IMPATT-diode oscillator is described. The oscillator's frequency was set by a simple, easily replaceable metal resonant cap, with fine tuning of about 30 MHz/mA being achieved by means of the diode current.

A 40-GHz Digital Distribution Radio with a Single Oscillator

New 40-GHs band digital radio equipment is described. In the equipment we adopted a new circuit configuration consisting of a single IMPATT diode oscillator which functions as both transmitter frequency converter and receiver load oscillator simultaneously. The principal system design factors, a unique IMPATT diode oscillator mount configuration and test results are described. The compact radio equipment is designed so that it ensures excellent cost performance for communication systems in local trunk service, even in short hop applications resulting from rainfall attenuation to the new band.

Optically induced AM and FM in IMPATT diode oscillators

Optical modulation of an IMPATT oscillator is investigated both theoretically and experimentally. Detailed computer simulations of the oscillatory dynamics are used to determine the basic mechanisms responsible for optical modulation and to examine the extent of and means for optimizing the optical response. It is shown that optically induced changes in the conduction current minimum and in the levels of carrier slowdown or depletion-region modulation are the primary mechanisms responsible for optical modulation. Amplitude modulation via an optical quenching of the oscillations is found to be the dominant response, although optical enhancement is also possible under certain conditions. It is demonstrated that substantial levels of FM can also be produced, despite the fact that the IMPATT susceptance is insensitive to illumination. The experimental results are found to be in general agreement with the predictions of the theory. It is concluded that the optical response of the IMPATT is sufficient to make optical modulation a useful technique.

Cavity Stabilization and Electronic Tuning of a Millimeter-Wave IMPATT Diode Oscillator by Parametric Interaction

A new technique is proposed by which both noise reduction and electronic tuning of a millimeter-wave solid-state oscillator can be realized by injecting an arbitrary low-frequency (several hundred megahertz or beyond) signal to the oscillator element which is provided with an additional high-Q cavity. This method has much wider tuning bandwidth than that of the conventional subharmordc injection locking technique. Presented are both experimental results and some theoretical interpretations by using an IMPATT diode oscillator.

Waveguide IMPATT diode oscillators with cap structure

Click to increase image sizeClick to decrease image size Abstract This paper describes the performance of Silicon IMPATT diode (p+ nn+) oscillators with cap structure operating in the IMPATT mode. Our experiments confirm that the oscillation frequency of IMPATT mode can be tuned by varying the cap diameter, which agrees with our calculations using radial transmission line theory.