Spike Leakage Research Articles

The effect of temperature variation on the transient response of RF PIN diode limiters for very high frequency applications

AbstractThis work presents the effect of temperature change on the capacitance of silicon PIN diodes and the resulting change in performance of RF limiters at very high frequency (VHF). Device temperatures were varied between −25 ºC and 100 ºC, with small‐signal parameters (including device capacitance) extracted at regular temperature increments and bias voltages from −20 Vdc to +3 Vdc using a multi‐bias parameter extraction method. It was found that the junction capacitance of the four PIN diodes under investigation increases with temperature, as expected from carrier lifetime behaviour, while results also confirmed prior observations of an inverse relationship between forward‐biased series resistance and temperature. Devices were subsequently tested in two different limiter topologies through high‐power transient measurements. It was found that the combination of increased capacitance and decreased resistance with increasing temperature increases the transient spike leakage and decreases the flat leakage of a limiter. It was also concluded that, for VHF, an anti‐parallel topology provides the best performance over a wide range of temperatures.

Spike leakage characteristic of limiter irradiated by high power microwave

In this work, the response characteristics of the microwave limiter under various high power microwave irradiation are investigated via both simulation and experiment, and the simulation results match those of the experiment well. When the input power exceeds 6 dBm, a spike leakage phenomenon is observed. As the input power increases, the rise time and pulse width of the leakage peak decrease, whereas the leakage power gradually increases. However, the leakage power of the plateau firstly linearly increases, then gradually decreases, and finally slightly increases. Moreover, the pulse width and repetition frequency have almost no influence on the characteristics of leakage pulse, and the leakage energy decreases as the injection power increases.

Analysis of coupling effect of high-power microwave on millimeter wave fuze

Aiming at the front door coupling effect of high-power microwave on millimeter wave fuze, the electromagnetic simulation software was used to irradiate a certain millimeter wave FM continuous wave fuze model, and the joint simulation was carried out with the front-end limiting circuit of the fuze. On this basis, orthogonal experiments are designed to analyze the influence level of signal parameters. When the high-power microwave signal frequency is aligned with the fuze working frequency, the simulation results show that the maximum coupling voltage at the end of the antenna can reach 188 V when the peak radiation field intensity is 60 kV/m. When the peak radiation field intensity is 40 kV/m, changing the characteristic parameters of the radiation signal and finds that the long pulse width signal is more likely to cause the thermal breakdown effect of the limiter; the rising time of the signal will affect the end of the antenna. When the peak value and pulse width of the coupled voltage waveform are fixed, the spike leakage voltage caused by the input signal with rise time of 5 ns is about 5.94 V, while the spike leakage voltage is 18.4 V when rise time is 0.1 ns, and the limiting circuit reaches saturation state faster. The orthogonal experiment shows that the spike leakage peak voltage is most affected by the rise time of the signal, and the signal peak is the largest, meanwhile the value has the second effect on it.

Miniaturised X‐band balanced microwave limiter based on thin film hybrid integrated circuit technology

On the basis of thin film hybrid integrated circuit technology, a miniaturised X-band balanced microwave limiter with low insertion loss (IL), low spike and flat leakage power and short recovery time has been presented. The balanced circuit configuration improves the power capacity of the PIN diodes, provides the absorptive load for the reflected power and also effectively tackles the problem of suffering high incident power. The measured results show that the balanced microwave limiter could suffer a pulse with 150 W peak power and 3% duty ratio while the leakage power is <10 mW, and the small signal IL of the circuit is <1.4 dB in the frequency range from 8.8 to 9.8 GHz.

Frequency-Selective Limiters Using Nonlinear Bandstop Filters

This paper presents a novel design for frequency-selective limiters based on reflection-mode nonlinear bandstop filters. This technique enables the use of low- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> lossy resonators for high- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> bandstop filter applications. Frequency-selective limiters described here achieve fast switching, high levels of power limiting, and flexible channel bandwidth. The prototype for a third-order device indicates 2-dB insertion loss for low RF powers. At high RF powers, it demonstrates 18-dB limiting level, 3-dBm limiting threshold, and 300-MHz limiting bandwidth. The switching speed is less than 10 ns, thus the spike leakage is minimized. The single-channel limiters are cascaded to provide limiting in wideband channels. The multichannel device is able to compress the dynamic range of the signals over 30 dB.

Spike leakage of thin Si PIN limiters

Thin PIN diode limiters (10 /spl mu/m or less) are used to protect sensitive microwave components from fast-risetime microwave pulses having energies exceeding 1 to 10 /spl mu/J. This paper analyzes and experimentally confirms the performance of these PIN limiters. It is shown that spike leakage is a transit-time effect that is controlled by the mobility of the carriers. A p-type background I-region should yield less spike leakage energy for a given thickness. It is proposed that the hysteresis effect observed when limiters are operated under cw conditions is due to space charge effects and stored charges remaining after the reverse-biased half cycle. Detailed agreement between the measured and calculated device voltage waveforms requires accurate modeling of the circuit parasitics because of the high rate-of-change currents arising from avalanching.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Gas-Breakdown Transmit-Receive Tube Turn-On Times

The first measured sub-nanosecond gas-breakdown microwave receiver protector turn-on times are reported. A technique to measure turn-on times as short as 0.35 ns is described. The turn-on time of an X-band gas-breakdown transmit-receive (TR) tube, both alone and when backed by a solid-state diode limiter (DL), is measured to be a small fraction of a nanosecond. The spike leakage energy and transmitted peak power are measured as functions of incident power up to 2 kW. Extrapolation of the results indicates that effective receiver protection might be achieved at gigawatt incident power levels.

Gas—Semiconductor Duplexer for Reduced Spike Leakage

Modern radars use ferrite-phaseshift circulator duplexer with TR tube in the receiver arm as a receiver protector. To reduce the spike leakage, diode limiter is needed after the TR tube. This paper gives guideline for selecting diode for low spike leakage and discusses the design consideration of gas-semiconductor duplexer. The constructed duplexer gave spike leakage of 0.004 ergs and flat leakage of 7 mW in the frequency range of 2.7 to 2.9 GHz at 800 kW (peak), 1 μs pulse width.

Design and Observed Characteristics of X-band PIN Diode Limiters

This paper presents design and observed characteristics of three types of limiters viz. passive limiter, quasi-active limiter and switched PIN diode limiter at X-band. Passive limiting, quasi-active limiting and switched PIN diode limiting of the order of 23 dB, 25 dB and 30 dB respectively were obtained at X-band. Using passive limiter as a TR-limiter after a gas-discharge TR-tube without keep-alive voltage, spike leakage of 0.07 ergs and flat leakage of 6.6 mW were obtained.

Radioactive (tritium) ignitors for plasma limiters

Radioactive ignitors using tritium as the active material are shown to be a reliable electron priming source for the RF discharge gap in plasma limiters when cascaded with a diode limiter. This result is based on ion-chamber studies of priming current strength, electron distributions, and thermodynamic and chemical stability of titanium-tritide electron sources immersed in low-pressure gases. The results of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</tex> -band measurements of the statistical distribution of output spike leakage amplitudes for overvolted discharge gaps and the threshold of breakdown of the RF gap in tuned plasma limiters containing titanium-tritide ignitors followed by a diode limiter show operating parameters equivalent to keep-alive plasma limiters. Experiments with the tritiated passive priming source substituted for the conventional dc keep-alive discharge show a greatly increased operating life in receiver protectors and gaseous TR's and the improvement of other important electrical parameters such as noise, reliability, and external driving power.

Ferrite-varactor X-band limiter

The conventional method of achieving reliable receiver protection for sensitive microwave receivers is to use a limiter consisting of a plasma stage and a varactor stage. The plasma limiter is used to reduce the incident power to a level that can be safely limited by the varactor device. The major power that is incident on the varactor is the spike leakage pulse that is caused by the slow response time of the plasma device. The fast response time of the varactor makes it ideal for reducing the spike energy. The varactor cannot be used alone because of its limited power handling capacity and a catastrophic failure mechanism.

Backward Diodes as Mixers at Microwave Frequencies

ABSTRACT This paper describes some exploratory work on the use of backward diodes as mixers at microwave frequencies. The physics of a backward diode and the parameters of a microwave mixer are briefly reviewed, indicating the choice of a point contact structure for the fabrication of a microwave backward diode. The fabrication of a backward diode by pulse bonding a gallium-plated wire to low resistivity germanium is described. These diodes are then assessed as mixers at a radio frequency of 9375 Mc/s, intermediate frequency of 45 Mc/s, and their mixer performance is compared with conventional mixer diodes. The results indicate that the noise figure performance of backward diode mixers is comparable to that of the best conventional mixer diodes available, but of great importance for use with local oscillators with limited power outputs (e.g. solid state oscillators and harmonic generators) is the ability of these diodes to operate satisfactorily with very low local oscillator power. The temperature dependency of the backward diode is shown to be less than for conventional mixer diodes. Their resistance to damage by mechanical shock and to burn-out by T.R. cell spike leakage is considered, and the low frequency noise properties of the backward diode are mentioned. Finally, it is shown that the backward diode shows interesting possibilities as a low level detector.

Duplexing and Switching with Multipactor Discharges

Multipactor discharges in high vacuum are employed as switching mechanism for high-power microwave duplexers and voltage controlled switches. The devices described handle peak powers up to 5.5 Mw at nanosecond switching speed. Further characteristics include freedom from spike leakage and practically instantaneous recovery times. A survey is given of the underlying multipactor theory. Developmental S-band multipactor duplexers and switches are described. Their advantages, limitations and potential improvements are discussed.

A Miniaturized Ferrimagnetic High Power Coaxial Duplexer-Limiter

The device to be described in this presentation is a miniaturized high power coaxial component performing within a single package the functions of circulation, power limiting, and preselection. Attention is principally directed to the limiting and preselection functions which are accomplished through the use of a crossed-strip gyromagnetic coupler which differs from those previously reported in that the second-order nonlinear process rather than the first-order process is the basis for its operation. This limiter has been tested independently at power levels as high as 8 kw and found to exhibit a flat leakage output less than 200 mw and a spike leakage energy of about 0.5 erg. The limiter is mechanically tunable over a frequency range greater than 10% in C band. At a fixed setting the 3 db bandwidth is about 20 Mc. The recovery time of the limiter is determined by the kickback of energy from the garnet spin system. Experimental values of this quantity will be presented. The duplexer-limiter package operates at peak powers up to 40 kw into a 2:1 antenna mismatch. Input VSWR at the transmitter port is less than 1.35. Insertion loss from the transmitter port to the antenna port is less than 0.7 db. Low power insertion loss from antenna port through the limiter to the receiver port is 1.0 db.

A novel approach to microwave duplexer tube design

Utilization of an encapsulated input window with an independent gas fill in a conventional type of broad-band duplexer tube separates the interdependence of the high power characteristics. Recovery time and arc loss ere determined predominantly by the input window design, whereas spike leakage energy and flat leakage power are determined bf the tube body design. The two portions of the tube are designed independently for optimum performance. The effects of geometry, gas pressure, and nature of the gas on the behavior of the high power characteristics have been investigated. ‘Phe factors determining adequate tube operation combined with reasonable tulle life are discussed.

The spike in the transmit-receiver (TR) tubes

The spike leakage signal from high-Q and band-pass tr tubes was recorded as a function of time by using high-speed oscillographic techniques. Transients as short as 0.5 millimicro-seconds (0.5 × 10-9seconds) were resolved. The variation of the 1B24 high-Q tr spike was determined as a function of time for several experimental parameters including the gas type and pressure, initial number of electrons in the tr gap, and peak incident power supplied by the transmitter. Oscillographic recordings show the tr spike leakage power from a commercial gas-filled 1B24 tr tube rises to a peak of 0.3w in a time interval of 6 mµsec. The spike leakage power from a 5863 three-gap band-pass tr tube rises to a peak of 3.6w in 7.5 mµsec. Threshold of microwave gas discharge breakdown measurements in helium gas are used to determine the electric field intensity in the 1B24 tr gap as a function of the waveguide power. From this, the electron motion during the spike interval is calculated. The results indicate that production of electrons in the gap can occur through ionization of the gas by the electrons' radio frequency energies, and by secondary emission at the gap surfaces, as well as through ionization of the gas by the electrons' energies of random motion.