Microwave mixer and detector diodes

Recent advances in microwave mixer and detector diodes are reviewed. Devices considered are germanium back diodes, silicon and gallium arsenide point-contact diodes, and Schottky-barrier diodes. Current work on low-barrier (n-type) Schottky diodes and high-burnout point-contact diodes is also described. Experimental results of CW and RF pulse burnout of these devices are summarized. Different approaches to improve the power-handling capability of Schottky diodes at S-, X-, and Ku-band frequencies are considered.     

Millimeter-wave point-contact and junction diodes

Millimeter-wave "point-contact" diodes are classed as conventional point-contact diodes (and modifications on them), which depend primarily upon a point-contact metal-semiconductor junction for their rectification properties; or as junction diodes with point-contact geometry, which are small-area millimeter-wave adaptations of the p-n junction diodes, normally made for use at lower frequencies by alloying, diffusion and other techniques. In a general way, techniques used in the fabrication of these various diodes are described; then the uses to which they have been put is detailed, and the best reported performance characteristics in various millimeter-wave applications are compared. Emphasis is put on demonstrated performance, but highly experimental and tentative laboratory results are freely quoted. Included are discussions of 1) conventional point-contact diodes of various semiconductors; 2) diodes having point-contact geometry but exhibiting electrical properties approximating those of alloyed and diffused p-n junctions, diodes made by planar techniques, a "thermoelectric effect hot carrier" diode, point-contact photodetectors and photoemitters; and 3) a millimeter-wave avalanche transit-time oscillator diode. The use of these diodes as millimeter-wave detectors, amplifiers, oscillators, harmonic generators, and modulators is considered.     

Carrier Pulses at Microwave and Millimeter-Wave Frequencies

This paper discusses some recent experimental results obtained using special gallium arsenide point-contact diodes for the generation of phase-locked carrier pulses in the microwave and millimeter-wave bands. Several methods of generating such pulses are described. 11.2-Gc microwave phase-locked carrier pulses of about 1.0-nanosecond base duration have been generated at a 160-megabit/second rate. These microwave pulses, which are generated directly from a baseband signal, normally have peak power levels in excess of 0.5 mw. Millimeter-wave phase-locked carrier pulses have also been generated at 56 Gc. These very high frequency pulses have a base duration as short as 0.25 nanosecond and occur at a 160-megabit/second rate. Furthermore, phase-locked carrier pulses have been generated at frequencies as high as 89.6 Gc. A simple method of generating nonphase-locked 0.3-nanosecond millimeter-wave carrier pulses directly from 1.92 gigabit/second rate baseband pulses has also been investigated. The experimental arrangement used to demonstrate the "turn on" and "turn off" principle of transient carrier pulse generation is described.     

Multidiode Switches (Correspondence)

The impedance of crystal diodes is known to depend on the applied bias voltage. This has suggested the use of diodes as switching elements in the control of microwave signal transmission. In the simplest form, the diode switch consists of a transmission line which is shunted by a diode. Coaxial cables as well as waveguides have been used for the transmission lines that are shunted by point-contact and p-i-n diodes. Slab line or coaxial switches where a diode is inserted in series with the center conductor of the line have also been developed.     

Millimetre-wave varactor multipliers

Results are presented of measurements on frequency doublers in the millimetre-wave region employing unencapsulated silicon varactor diodes types ZC103 and ZC70D and a gallium-arsenide/phosphor-bronze point-contact varactor.     

Hot-electron noise limitations in submillimetre-wave Schottky-barrier mixer diodes

The noise from small-area platinum gallium-arsenide Schottky-barrier mixer diodes has been measured at 4 GHz, to compare high-field (hot-electron) noise in diodes with different doping densities and anode areas. In the present state of technology, submillmmetre-wavelength mixer diodes should be fabricated from gallium arsenide with a doping density of about 1017 cm?3.     

Current-gain characteristics of Schottky-barrier and p-n junction electron-beam semiconductor diodes

Measured and calculated current gains are presented for silicon, gallium-arsenide, and gallium-arsenide-phosphide electron-beam-semiconductor Schottky-barrier diodes. Silicon and gallium-arsenide-phosphide (GaAs0.7P0.3) diodes, having comparable critical voltages, provided current gains of 1400 and 960, respectively, at the beam voltage of 9 kV. A gallium-arsenide diode had a gain of 2100 at 12.7 kV. It is shown that Schottky-barrier diodes provide a good diagnostic tool for measurement of energy per electron-hole pair in semiconductors. The average pair energies for silicon, gallium arsenide, and gallium arsenide phosphide, determined by use of these diodes, were 3.6, 4.6, and 5.2 eV, respectively. Expressions for static and time-dependent current gains are derived for abrupt p-n-junction EBS diodes based on measured and simplified (constant) lineal densities of secondary-electron generation. It is shown that the current gain of p-n junctions is generally lower than that of Schottky-barrier diodes and decreases with increasing density of the semiconductor. For shallow (<0.2 µmr) silicon junctions, the calculated current gain is only slightly smalle. (<8 percent) than that of comparable Schottky-barrier diodes Measurements performed on a relatively deep (0.8 µm) silicon p-n junction, which provided a current gain of 2500 at the beam voltage of 13.6 kV, are in good agreement with the theory. The gain of this junction was typically 40 percent lower than that of a comparable Schottky-barrier diode. This difference was significantly greater for gallium arsenide as a result of its higher density. Approximate expressions and calculations are presented for estimating frequency limitations of p-n-junction EBS targets.     

Microwave Amplifiers Employing Integrated Tunnel-Diode Devices

A series of shunt-tuned integrated microwave tunnel-diode devices utilizing unencapsulated beam lead tunnel diodes and including tuning and stabilizing circuitry have been fabricated using tantalum thin-film technology for use as the active element in microwave reflection amplifiers. The theoretical properties of such devices have been explored, and data relating to their design and measured performance are presented in detail. Finally, the successful use of these devices as the active elements in a series of absolutely stable circulator-coupled reflection amplifiers at 4 and 6 GHz has been demonstrated.     

Low-Noise Millimeter-Wave Receivers

Over the past several years, significant improvements have been made in solid-state devices (that is, avalanche diodes, Gunn diodes, varactors, mixer diodes, etc.) that have enhanced the overall capability and low-noise performance of millimeter-wave receivers. With these improved devices, it is now possible to configure completely solid-state low-noise millimeter-wave receivers. As is similar in the microwave region, low-noise parametric amplifiers, broad-band low-conversion-loss mixers, and solid-state local oscillators are now available. Furthermore, cryogenically cooled parametric amplifiers and mixers are also being developed that will result in achieving the ultimate in system sensitivity. With the flexibility offered by these completely solid-state millimeter-wave components, it is now possible to design the optimum system configuration for the intended application whether it be an advanced communication system, a sophisticated EW application, a RADAR system, a radiometric system, or satisfying any of the numerous receiver requirements that are being evolved. This paper explores the trends that are being developed in the millimeter-wave region and their application to system design. The performance criterion of various receiver systems and their sensitivity requirements are presented. A review of the system operating noise temperature concept and the method by which it can be determined and its applicability to low-noise components is demonstrated. A review of the state-of-the-art of low-noise systems and experimental data obtained in the millimeter-wave region is also presented.     

Reciprocity in silicon Schottky-barrier diodes

Reciprocity has been examined at X band for low-noise silicon Schottky-barrier diodes by measuring the forward (r.f. to i.f.) and reverse (i.f. to r.f.) conversion losses by the heterodyne method. Reciprocity held for the silicon Schottky-barrier diodes, proving that their low conversion-loss behaviour is due to the nonlinear barrier resistance and not to parametric amplification caused by a nonlinear barrier capacitance. For comparison, silicon epitaxial point-contact and germanium point-contact diodes were also examined.     

Two-diode parametric amplifiers

Analysis suggests that very useful performance may be achieved in parametric amplifiers incorporating two varactor diodes. The most interesting configuration is a bandpass amplifier in which the varactors are the shunt capacitive elements, operated with a phase shift between diodes of 90° at the centre signal frequency and with the diodes mounted with opposite polarities. With inphase pumping this gives unilateral operation and a large potential bandwidth.     

The variable-capacitance parametric amplifier

The physical principles involved in the operation of the major types of variable-capacitance parametric amplifiers are reviewed and a qualitative explanation is given of the variable-capacitance effect in semiconductor diodes. The utilization of these principles and also of these diodes in a number of experimental, low-noise amplifiers is described. A comparison is given of the best noise performance obtained to date with experimental vacuum-tube amplifiers with that of parametric amplifiers. This paper is directed primarily at nonspecialists who wish to acquire some familiarity with a new and fast-moving field.     

Glass-ceramic-copper microwave encapsulations and mountings

Methods of preparing microwave encapsulations for gallium-arsenide diodes, using a glass-ceramic-copper combination, have been developed. These encapsulations are not only cheaper than alumina- or beryllia-based ones, but the glass ceramic used has the additional advantage of more favourable microwave properties and permits a considerably greater flexibility of design of components and encapsulations than was previously available. Selected patterns can be produced in the dielectric, over large or small areas, to the tolerances compatible with integrated-circuit technologies. This opens up new possibilities and many applications over a wide range of frequencies.     

Solid-State Microwave Amplifiers

The maser and the parametric amplider form a new class of microwave amplifiers which can exploit the properties of bound electrons in a solid. These amplifiers have several common characteristics, among them being their very low-noise performance. This paper reviews the method of operation of these amplifiers, discusses the performance achieved and achievable by the various versions, and points up some of the difficulties involved in effectively utilizing the extremely low-noise figures obtainable. A bibliography is included in which an attempt has been made to include all published papers on masers and parametric amplifiers.     

Nonlinear properties of IMPATT devices

The basic principles of IMPATT diodes as microwave devices are reviewed and the current status of these devices concerning power output and efficiency is given. The main purpose of this paper, however, is to discuss the nonlinear properties of these diodes which are useful in the design of amplifiers, oscillators, and other microwave devices. The main results of this paper are obtained from a digital computer analysis where an approximate, but realistic, diode model is employed. A detailed comparison of complementary silicon diodes as well as GaAs diodes concerning power output and efficiency is given. The effects of doping profile, current density, temperature, and material parameters on the performance of these devices have been investigated and are summarized. Saturation effects which limit the efficiency and power output of these devices are described and optimum efficiencies which can be achieved for various doping profiles are given. A comparison between single-sided and double-drift diodes in both silicon and GaAs is also presented.     

Two-port amplifiers using gallium arsenide as the active element

Two-port transmission amplifiers using gallium arsenide as the active element have been designed and built. These are capable of providing more than 25 dB gain in the vicinity of 2 GHz with a saturation power of more than 1 watt. Reciprocal operation can be obtained and the degree of reciprocity controlled by a relatively simple adjustment of the microwave circuit.     

Diffused silicon nonlinear capacitors

Diffused silicon nonlinear capacitors have been fabricated by solid-state diffusion. The resulting graded p-n junction is a planar structure which permits low series resistance Rsrelative to the minimum capacitanceC_{min}, which is measured at a reverse voltage slightly less than the breakdown voltage. A cutoff frequencyf_{c} = (2piR_{s}C_{min})^{-1}is used as a figure of merit; values up to 150 kmc have been obtained. These "varactor" diodes may be used as UHF and microwave amplifiers and as harmonic generators. The noise figures of the UHF amplifiers are better than the best noise figures obtainable by present electron-tube techniques. These diodes are also efficient harmonic generators.     

6毫米波段(40～60GHz)砷化镓体效应二极管

通过对体效应二极管在毫米波高端工作特点的分析,详细讨论了6毫米GaAs体效应管的设计原则.着重探讨了器件设计中热参数与微波寄生参数要求间的矛盾,推导得到一组计算公式用以确定器件管芯与封装的设计参数.介绍了采用GaAs/AsCl_3/H_2汽相n~#外延、无氰无铵电镀金热沉、双金带十字引线等措施的器件制备工艺.研制的二极管在V波段的最大输出功率达130mW,最高效率为3.8%;以谐波方式在94GHz下输出大于10mW.本文还重点报道了器件可靠性研究的情况,器件预期的室温平均工作寿命超过1.4×10~8小时.使用该器件的振荡器已成功地用于常温50°K低噪声参放及微波遥感等方面.     

High-efficiency oscillations in gallium-arsenide avalanche diodes

Some preliminary results are reported for an analytic theory of high-efficiency microwave oscillations in gallium-arsenide avalanche diodes. Design and performance criteria are deduced for p+?n?n+ and n+?p?p+ structures, and a comparison is made with experimental work.     

Polarity reversal in the detected output of a point-contact diode at submillimetre wavelengths

Anomalies in the detected output-voltage polarity of point-contact diodes at submillimetre wavelengths have been observed and are thought to be due to two competing mechanisms: (a) Schottky rectification, and (b) thermoeletric effect of heated majority carriers in the region of the junction. Optimisation of point-contact diodes for the thermoelectric effect may produce improved n.e.p.s. at submillimetre wavelengths.