Peak Power Handling Capability Research Articles

Lateral PIN diodes for silicon-on-insulator monolithic microwave integrated circuits

Surface-oriented lateral mesa PIN diodes have been fabricated for the purpose of evaluating the feasibility of a silicon-on-insulator technology for microwave applications. For these devices, heavily doped p and n regions are formed from ion-implanted polysilicon diffusion sources which abut opposite sides of an intrinsic rectangular-shaped mesa, and electrical contact to the injecting contacts can be made with low parasitic series resistance. Devices for process evaluation were fabricated using a single-crystal silicon substrate (as opposed to recrystallized silicon-on-insulator films). Both d.c. and 3-GHz electrical characteristics indicate the desired conductivity modulation of the intrinsic region under forward bias. Moreover, the large breakdown voltage which is observed indicates that high peak-power handling capability should be possible.

A Study of Electric-Field Breakdown in E-Plane Lines at Centimeter and Millimeter Wavelengths

The microwave field breakdown in various E-plane transmission lines is investigated theoretically in the frequency range from 1 to 140 GHz. The influence of frequency, pressure, temperature, and inhomogeneity of the applied field on the breakdowm field value is discussed. The peak power-handling capability of unilateral and bilateral finlines is determined theoretically using a quasi-static evaluation of the field distribution. It is found that finlines, even with small gap widths, can handle pulse power levels well above the capability of present solid-state devices. Preliminary breakdown measurements in X-band have confirmed the validity of the theoretical predictions.

Planar Meanderline Ferrite-Dielectric Phase Shifter

This paper presents the design of meanderline circuits with multilayer ferrite-dielectric embedding. New expressions are developed for the even- and the odd-mode admittances for an infinite meanderline in such a structure. It is shown that the effective dielectric constants and the effective relative permeabilities for some of the multilayer structures are simply related. An efficient synthesis routine for the design of meanderline circuits is described. Effect of different parameters on the phase shift has been studied experimentally. It is indicated that the present structure can result in a compact phase shifter with an improved figure of merit, peak power-handling capability, and temperature stability.

X-Band High-Power Multipactor Receiver Protector

High vacuum devices incorporating the secondary electron resonance phenomenon have been used for several years in receiver protection circuits for high-power high-pulse repetition frequency (PRF) RADARs. These are known as multipactor devices. Recent technological developments have increased the peak-power handling capability and bandwidth of airborne-qualified devices to 50 kW and 12.5 percent respectively. Life tests on multipactor devices have demonstrated 2500 h of failure free operation.

New concept of high peak-power junction circulators

The influence of the steady magnetic field H on the peak-power handling capability of a junction circulator is studied. Particularly when this magnetic field is above the limit magnetic field Hlim, no nonlinear. effects appear in the junction circulator. This principle of operation has been applied for the study and the realization of three port KU band and four port X and KU band junction circulators with high peak-power handling capability. The use of new Sm-Co <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> permanent magnets permits the realization of lighter and more compact circulators and differential phase-shift circulators well-known for high-peak power applications.

X-band high-peak-power junction circulator: Influence of the static magnetic field

The influence of the steady magnetic field <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</tex> on the peak-power handling capability of a junction circulator is studied. A similarity between the variation of the critical power P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> (measured on the circulator) and the critical field h <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> (measured in cavity) versus static magnetic field is observed. It is particularly attractive to apply a magnetic field <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</tex> whose value is near the limit magnetic field H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">lim</inf> for which nonlinear effects disappear. In this case the critical power is very high. In order to prevent the decrease of the magnetic field (delivered by the magnet) with increasing temperature, it is desirable to use samarium-cobalt magnets so that the magnetic field <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</tex> is near the limit field H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">lim</inf> . When the magnet is temperature unstable (for instance, barium ferrite) it is possible to achieve high peak-power performance at temperatures above room temperature with relaxing-ion-doped garnets but at the expense of higher insertion loss.

Selection of ferrite materials for microwave device applications

This paper deals with some general rules for selecting materials for linear ferrite devices. Four steps are required for material definition. 1) An analysis which relates device performance to the intrinsic complex permeability tensor [μ] and to the complex permittivity <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\epsilon = epsilon' - j\epsilon"</tex> of the material. 2) A determination of the internal biasing field in the ferrite from the applied biasing field and shape-dependent demagnetizing factors. 3) An estimate of the required saturation magnetization M <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf> based on a consideration of lowest operating frequency, peak RF power level, and maximum desirable biasing field. 4) A specification of ferrite composition and mechanical properties resulting from consideration of magnetic loss, temperature-dependence of the device, peak-power capability, and mechanical stability. Materials selection is done from the particular ferrite system which comes closest to the required saturation magnetization and offers the best compromise with respect to magnetic loss, temperature stability, and peak-power handling capability.

An Extremely High Power X-Band Three-Port Circulator

The modifications of typical ferrite materials by either hot-pressing or the addition of fast relaxing impurities are compared in a three-port circulator. A standard MgMn ferrite with empirical formula Mn0.08Mg1.25Fe1.67O4± was tested in the three-port circulator model. It showed an onset of nonlinear behavior at 20 kW. By hot-pressing, the peak power level was extended to 200 kW with 0.1 dB rise in insertion loss, and to 500 kW with 0.25 dB increase in insertion loss. A gadolinium-substituted garnet with empirical formula 3(Y0.6Gd0.4)·5(Fe)O12 was tested in the same geometry. It exhibited a threshold power level of 10 kW. A 4% substitution of dysprosium greatly extended the peak power handling capability of the three-port circulator. No increase in insertion loss over low-power readings was noted up to 500 kW peak.

Theoretical Analysis of Twin-Slab Phase Shifters in Rectangular Waveguide

The differential phase shift and the losses to be expected in phase shifters using two oppositely magnetized ferrite slabs located symmetrically in a rectangular waveguide have been calculated for various locations and thicknesses of the ferrite slabs. For small thicknesses of the ferrite slabs, the differential phase shift increases rapidly with increasing thickness reaching a maximum when the thickness is approximately 1/10 of the free space wavelength. The calculated insertion loss of a 360-degree phase shifter decreases with increasing slab thickness for small thickness, reaching a minimum when the thickness is approximately 1/25 of the free space wavelength. The minimum insertion loss calculated with the assumption that the imaginary part of the diagonal component of the permeability tensor is 0.01 and that dielectric loss can be neglected is approximately 0.85 dB. The peak power handling capability has also been analyzed. It can conveniently be summarized in terms of a high-power figure of merit. For reasonably high values of this figure of merit, a peak power capability of the order of 100 kW is anticipated.

Double-Ridge Waveguide for Commercial Airlines Weather Radar Installation

This paper describes the design and development of a double-ridge waveguide designed to propagate both C-band and X-band (5,400 and 9,300 mc) so as to allow for a common waveguide installation in commercial airliners which could use either a C-band or an X-band weather penetration radar. This double-ridge waveguide is capable of propagating over the desired frequency range with single mode operation only; it yields attenuation at C-band which is only slightly higher than that of normal C-band waveguide and has somewhat reduced attenuation at X-band compared to standard 1 X 1/2 rectangular waveguide. This double-ridge guide has been adopted by Aeronautical Radio, Inc. and is specified in their Characteristic No. 529 entitled 5.7 Cm Weather Penetration Airborne Radar. This paper also gives an analysis of the calculated guide wavelength in this double-ridge guide, attenuation, and peak power-handling capabilities; and compares the results of these calculations with measured data. Peak power-handling capability for this double-ridge guide is well within the requirements of this application. The testing procedures used for high-power breakdown measurements are described. This paper also covers the development of double-ridge waveguide flanges, elbows, bends, twists, transitions, and flexible waveguide for use over this extremely broad band.