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The work performed was circuit analysis and power handling capability of PIN diodes for use in C-Band. The 'T' model phase shifter provided the largest phase shift per diode, but was capable of duplexing less than one tenth the required power level. The 'B' model phase shifter did not provide enough phase shift to be of use as a duplexer. The 'W' and 'H' model phase shifters require high power tests before evaluation can be performed. The TR type switch shows some signs of promise. Diode junction temperature tests were performed. (Author), See also AD-611 285.

This thesis discusses the fluctuations of noise in a two and three dimensional semiconductor containing a p-n Junction. We consider a rectangular parallelepiped single crystal It is bisected in the longest dimension by a p-n Junction. Since this dimension is several diffusion lengths it can be considered infinite. In the transverse plane we investigate the case where both dimensions are finite, and then the case where one is finite and the other infinite. In the p-n junction the noise is the result of fluctuations in the minority carrier density. in a p-n Junction there are two classes of minority carriers: 1. holes in the n-type material, 2. electrons in the p-type material. Since both the and electron density fluctuations are similar, we discuss only the former in detail. We investigate the differential equations for a two and three dimensional semiconductor with a p-n Junction and find the inhomogeneous form of these equations. These equations are solved with the help of the scalar and tensor green's function. The noise problem is solved by using these equations as Langevin equations and interpreting the distributed sources as random forces. Then the noise current spectrum is determined with stochastic process theory after deriving the sources from basic physical models and the theory of stationary, ergodic, Markovian processes. We consider two cases of surface recombination velocity on the transverse surfaces: infinite s and finite s. For the infinite case, we get the exact solution which provides an upper bound for the noise spectrum for large a. For an arbitrary S we get a solution but have confidence in the solution for only small s. Therefore we have obtained a complete solution for the two cases of practical interest: large and small surface recombination velocity. These cases should prove of interest in the analysis of noise phenomena in semiconductors.

A UHF switch matrix was developed for the LES-6 satellite to electronically despin the antenna beam as the satellite rotated on its axis. Initially, a study was carried out to determine the optimum antenna system and switch configuration for the constraints of satellite geometry and minimal complexity. Two such switch matrices, operated by logic circuits and sun and earth sensors, were used on the satellite, one to excite two adjacent of eight pairs of antenna dipoles, and the other to excite two adjacent of eight pairs of cavity-backed slots. The polarizations of the signals from the dipoles and slots are orthogonal and by adjusting the phase difference to 90 degrees, the satellite will, in normal operation transmit and receive on right-hand circular polarization. Furthermore, by squinting the beam formed by two element pairs +11.25 degrees or -11.25 degrees from the center line of the element pairs, any of 16 beams can be formed which are equally spaced in azimuth about the satellite. Each switch consists of three parts, namely, a hybrid to divide the input power into two equal parts, a 2P2T section which switches phase, and two SP4T sections to switch on two antenna pairs. The switch was built in strip transmission line using PIN diodes in series with the inner conductor as the switching element.

The design criteria for an optimum semiconductor receiver protector circuit are presented. Using these criteria the characteristics of a selfswitching PIN diode limiter for use in the 420 mc range are derived. Measured data on a four diode switch are presented and compared with the program requirements. Two approaches to the 420 mc circulator design are described along with measurements of high power and low power performance.

This report was performed on the C-band portion. All work performed on the Ku-band investigation was concerned with full height Ku-band waveguide diode mounts. PIN and varactor diodes were measured using forward DC bias to simulate high power isolation and zero bias to provide the low loss condition. Additional work was carried out utilizing high burn out crystal detectors to provide the forward bias for the PIN and the varactor during high power tests. High power tests during this quarterly interval resulted in the successful operation of a two stage switched limiter. Operational data is given for peak powers up to 1,000 watts.

An investigation has been made to determine the feasibility of using PIN DIODES AS SWITCHING ELEMENTS TO CONTROL 150 PS, 8 MW impulse signals. Single diodes in shunt and in series with a 50-ohm stripline were studied, as were series stacks of up to 8 diodes. It is found in the series configurations that good signal fidelity obtains in forward bias at all signal voltages, with insertion loss being a function of I region thickness. At higher signal voltages it is an even stronger function of the signal since diode conductance significantly increases with internal voltage stress.

The basic theory of transit-time delay diodes is presented, and their maximum power output calculated. This output is about 13 of that calculated for conventional transistors on a similar basis, but the maximum operating frequency should be much higher. It is shown how the maximum voltage decreases with frequency, leading to a lower impedance level. Experimental devices designed to make use of delay in the collector depletion layer did not show negative resistance because of difficulty in operating at the required voltage. The reverse recovery of a PIN diode is calculated and shown to be useful for harmonic generator applications. The transition time from on to off is determined by the transit time for carriers across the I region in space charge limited flow, and by the diode capacitance. Experimental epitaxial diodes showed the expected performance of less than 1 ns turn-off time in a diode with 15 pf capacitance.

For the purposes of studying the response of silicon, lithium-drifted p-i-n junction detectors to electron sources, an extrapolation chamber and its associated circuitry were set up and put in working condition. The measurement of surface dose rates for carefully specified geometries has begun, using a liquid thallium-204 thick source.

Single limiter capabilities of 5.0 KW and 1.0 KW at S and X-bands respectively were established with associated reasonably low values of insertion loss. By combining two of these units with 3 db hybrids, this capability can be doubled. In addition, X-band tests were successfully run up to 2.5 KW peak which indicates a further in crease in power handling capability can be achieved. However, some diode development remains to be done since insertion loss for this case was 1.5 db. This value is too high with respect to the design goal of 1.0 db.

Improvement has been made in both theoretical analyses and fabrication techniques of silicon carbide photovoltaic diodes. A P-I-N junction theory of photodiodes has been developed which includes all carrier transport parameters. This general theory is compared with the simple model developed previously for the explanation of the dependences of the peak response wavelength on the junction depth and temperature. Eight silicon carbide ultraviolet detectors were fabricated. Using improved fabrication techniques these detectors had a lower electrical impedance and higher response than detectors previously fabricated. The feasibility of using aluminum nitride, a high temperature semiconductor with a band gap wider than silicon carbide, in the fabrication of ultraviolet detectors was also studied. The sublimation technique was used to grow small hexagonal crystals about 2mm across, and several epitaxial methods were used to grow single crystal layers of A1N on both SiC and A1N.

The most promising approaches for bubble domain sensing are (1) magneto-resistive detectors (MRD), and (2) magneto-optical detectors (MOD). These two types of detectors are the subject of the report. For MOD a garnet film with high Faraday Rotation (FR) is desirable. Data are presented showing the effect of Bi-doping on the FR of YIG. Data are also presented on the FR of a large number of other rare earth iron garnets. The data indicate that a lens-less all-solid-state MOD is feasible using an edge-emitting light-emitting diode of GaAs:Al and a bubble film of Bi3-2xCa2xVxFe5-x012 (x approximately 1.1) grown on a nonmagnetic garnet substrate such as Sm3Ga5012:In, or a Bi-containing LPE film on a Gd3Ga5012 substrate. For a MRD, the advantageous design is one that utilizes a chevron expander with the detector formed by interconnecting the chevrons in a column to form a staggered continuous circuit. The permalloy thickness for the detector should be the same as that for the propagation elements. (Author)

This report discusses the work accomplished during the fourth and fifth quarters of a study effort to develop electronically tuned matching networks intended for use with a VHF whip antenna in the 30 to 76 MHz frequency range. RF power levels of 10 watts and 100 watts are being considered. A discussion of the 10 watt matching network design is presented along with test results which demonstrate the power handling and matching efficiency capability of the assembled network. The design and initial test results of a reactor to be used in the 100-watt network are also given. A control and monitor chassis which houses all the necessary circuits and power supplies required to operate either the 10-watt or 100-watt matching network is described. Finally, a revised and more detailed network tuning procedure flow chart for use in conjunction with the control and monitor chassis is presented. (Author)

This report presents the results, conclusions and recommendations stemming from a program to develop and evaluate a C-band, medium power, all solid-state, microwave integrated circuit module having polarization diversity capability and containing also the necessary phase shifters and antenna elements to provide electronically controlled beam steering when used as a building block in a phased array. In addition, the module contains the necessary components to provide complete receiver front-end functions. The following components are included in the module: a 3-port junction circulator, a 2-branch hybrid coupler, four meander line phase-shifters, a dual input circular waveguide antenna, a power limiter, a local oscillator, several RF filters, a balanced mixer, and an IF preamplifier. The size of the module is 1.2-inch x 1.2-inch x 5.0-inch including connectors and the antenna. Resulting designs, performances and observations concerning the behavior of these devices as separate components are also discussed. (Author)

This report discusses the areas explored during the third quarter of a study effort to develop electronically tuned matching networks intended for use with VHF whip antenna in the 30 to 76 MHz frequency range. RF power levels of 10 watts and 100 watts are being considered. The high temperature and high RF flux density performance characteristics of three ferrite materials are graphically presented and compared. The relative merits of the materials for this specific application along with mechanical design techniques which would allow maximum power handling capability per unit ferrite volume are also discussed. The final section of this report discusses, using flow charts, a direct, logical, tuning technique which may be used to control, electronically (digital or analog) or manually, the matching network. (Author).

The aim of this project was to explore the feasibility of monolithic integration at microwave frequencies with epitaxially grown silicon devices on sapphire substrates. Major emphasis was placed on developing the necessary processing techniques to fabricate a truly monolithic Impatt oscillator. In the course of the project, a PIN switch AM modulator with interdigital electrodes and air-bridge cross-over connections was employed as the experimental vehicle for technology development. A silicon-on-sapphire Impatt oscillator was fabricated and was successfully operated under pulsed conditions at 13.8 GHz, demonstrating the feasibility of monolithic integration at microwave frequencies. A novel quasi-monolithic approach which involved thermal compression bonding of high-quality silicon device structures on low-loss insulating substrates with high thermal conductivity is suggested for microwave integrated circuits. (Author)

Part I discusses noise in p-i-n junction diodes in which the i-region is so short that the characteristic varies as (exp(eV/beta kT)-1) with beta is similarly ordered to 1 at low voltages and with beta slowly decreasing at higher voltages. It is shown that the noise can be represented as 1 sq = 2eI delta f + 4 beta kT(g-g sub o) delta f. Here the first term represents shot noise and the second term thermal noise of the incremental conductance (g-g sub o). Part II discusses noise in p-n-p-n diodes. The noise is 1/f noise and is quite large. There are two enhancement processes at work: (1) The internal feedback in the device gives already an enhancement of the noise emf for open input. (2) Because of the very small internal resistance R sub in of the device, the short-circuit noise current is very large. There is a sharp peak in the noise current where R sub in goes through zero. (Author)

The desired variation in phase shift is produced by electronic modulation of the width of a rectangular waveguide which results in a change in the phase shift per unit length along the waveguide. The change in effective width of the waveguide is accomplished by means of a PIN diode that is literally distributed along a sidewall of the waveguide. Among the tasks required study were (1) propagation analysis for the diode-loaded waveguide to determine the relevant parameters, (2) fabricating and evaluating the distributed PIN diodes, and (3) forming a phase shifter using these diodes. Computed and measured data are presented for waveguides loaded with silicon slabs of various conductivities and for distributed PIN diodes. The work demonstrated the potential feasibility of the distributed PIN phase shifter.

The report encompases the fabrication of four Interference Cancellation Systems (Model ICS-1101-UHF-3) fabricated for UHF communication applications. The systems are for extensive test and evaluation in an operational environment by field personnel. The systems are capable of cancelling up to +20 dBm interference levels from three transmitters simultaneously and provide outputs for up to four receivers without degrading a receiver with -110 dBm sensitivity (S+N)/N=1. The technical problems encountered, the solutions employed, and test data on the final systems, as well as a description of the various circuits, are discussed in the report. (Author)

Large p-i-n diode structures suitable for use in millimeter wave image conversion panels have been developed. Typical dimensions are 0.25 cm in width by 0.28 cm in length by 0.11 cm in thickness between injecting contacts. Ion implanted arsenic and alloyed aluminum form the n and p junctions, respectively, on 18 kiloohm - cm silicon. Image conversion panels operating at 10 frames/sec and containing up to 1000 diode elements can be constructed using the present diodes. (Author)

Work under the contract is reported in the following areas: Harmonic generation efficiency of carrier storage diodes; Determination of doping profiles in semiconductor layers by harmonic generation measurements; Transit-time-controlled switching process in a wide p-i-n diode; and Investigation of semiconductor-insulator interface state properties.

The report covers work done during the past grant period, which included studies of the performance of wide silicon p-i-n diodes and IMPATT diode oscillators, and the development of a microwave noise measuring system. Chapter 1 describes observations of unusual properties of wide p-i-n diodes with respect to transmission of microsecond and submicrosecond pulses and VHF sinusoidal signals. Champter 2 presents a theoretical analysis of the noise generated by a Read diode IMPATT oscillator in the presence of a small but not negligible signal current. The analysis points to a possible method of accounting for nise output in the neighborhood of the signal frequency of such an oscillator. Chapter 3 describes a microwave noise measuring system which is used to measure AM and FM noise spectra of oscillators. Measurement results are given. (Author)

A system has been developed for generating nanosecond-order pulses of microwave energy with the output pulse amplitude considerably higher than the input CW source level. The system uses a PIN diode switched waveguide cavity for a pulse forming device. The output pulse width is shown to be directly proportional to the actual cavity length. Minimum pulse width and degree of enhancement of the output amplitude are shown to be a function of the switching time and loss characteristics of the switch. Pulse widths as narrow as 4.3 nsec and enhancements as high as 4.8 dB were obtained using pulse repetition rates from zero to 500 KHz. The output level enhancement feature of this system is its chief advantage over other nanosecond RF pulse generators. Other advantages of the system are its relative low cost, simplicity of tuning, versatility of pulse width and repetition rate, and its adaptability for rugged construction. (Author)

A wideband instantaneous microwave frequency-measurement receiver has been specifically developed to provide high quality pulse-by-pulse frequency measurements suitable for automatic signal-sorting applications. The receiver is characterized by high intercept probability, good sensitivity, and an excellent frequency-sorting resolution which is maintained over a very large continuous dynamic range. Measurement rates exceeding one hundred thousand per second can be accommodated. (Author)

Double injection diodes are described which, depending upon the kind of deep level doping impurities empolyed, exhibit instabilities and coherent and/or noisy oscillations in normally positive resistance regions of the v-i characteristics. Similar oscillations in n-type bars of Silicon compensated with certain deep level impurities are also described. The influence of deep levels on these phenomena is discussed. Some preliminary results on experiments with (As sub x P sub 1-x) light emitting junctions are presented. (Author)

The patent describes a modulator where a transmission line feeds a PIN diode with an information signal. A modulating signal biases the diode so as to switch the diode between forward and reverse bias at an r.f. frequency. The PIN diode exhibits variable capacitance during switching which results in the generation, on the transmission line, of a single sideband modulated signal.

Increased use of radio communication has brought use of higher and higher frequencies in the electromagnetic spectrum. While transmission frequencies have risen, intelligible and useful information is still contained in audio and other low frequency signals. Hence modulation, the electronic process of mixing these two signals, is a fundamental part of this development. Unfortunately, modulation methods used with low frequency carrier circuits do not work well, if at all, at microwave carrier frequencies. The PIN diode is a simple semiconductor device whose properties lend it to effective use as a modulator at microwave frequencies. This paper is concerned with a brief theoretical presentation of actual modulating circuits and discussion of their operation and results obtained. (Author)

The research in this quarterly covers the period 1 June 1968 through 31 August 1968. The following areas of research are reported: Application of Adaptive Components and Techniques to Electronic Warfare problems; Wide-Open, Instantaneous-Frequency Measurement Techniques; Application of Self-Adjusting Voltage Filters to Adaptive Signal Sorting; Navy Consulting; Waveform Synthesis and Special Measurement Instrumentation; Solid-State Microwave RF Sources and Companion Elements. (Author)

Efforts were directed towards the evolution of a single pole, double throw RF switch which has been developed by the Solid-State Circuits Division at Microwave Associates. The RF switching element used is a PIN diode. It will be seen that this report stresses the development of a diode with the proper characteristics to function ideally in this application. The design goals have all been realized and the methods used to accomplish this constitute the body of this report. (Author)

Efforts were continued on the establishment of a PEM on 1.0 lw solid-state X-band microwave TR-ATR switch as used in a balanced duplexer. Manufacturing techniques and all drawings were reviewed and are now complete for preproduction. The assembly and test procedures were completed and are being compiled for inclusion in a manual for preproduction manufacturing operations. Equipment requirements and test bench block diagrams are available for each step in the electrical tests and measurement procedures. Specifications for the crystal bias diodes, PIN and varactor diodes were determined and diodes were ordered. The life test on unit LM 28 continued during this period. (Author)