Bernard Eugene Sigmon

L-band transmitter using Kahn EER technique

This paper describes a 20-W peak-envelope power linear L-band transmitter based upon the Kahn envelope-elimination-and-restoration technique. A double envelope-feedback loop assures high linearity. The radio-frequency (RF) power amplifier employs a two-stage monolithic-microwave integrated-circuit driver amplifier and a 20-W power amplifier biased for class-AB operation. The class-S modulator includes a high-speed comparator and 1/2-/spl mu/m heterojunction field-effect transistors in its output stage. A double envelope-feedback loop assures both high linearity and time-delay equalization for RF bandwidths to 150 kHz. With a two-tone signal, the transmitter achieves an efficiency of 56% at full power (41 dBm), and 35% at 18 dB into back-off. The third-order intermodulation distortions for a two-tone signal vary from -30 to -40 dBc over a 20-dB range of back-off. For quaternary phase-shift keying, the first and second adjacent-channel powers are -48 and -57 dBc.

High-efficiency L-band Kahn-technique transmitter

This paper describes a 20 W PEP linear L-band transmitter based upon the Kahn envelope-elimination-and-restoration technique. A double envelope-feedback loop assures high linearity. The RF power amplifier employs a two stage MMIC driver amplifier and a 20 W PA biased for class-AB operation. The class-S modulator includes a high speed comparator and 0.5 /spl mu/m HFETs in its output stage. A double envelope-feedback loop assures both high linearity and time-delay equalization for RF bandwidths to 150 kHz. With a two-tone signal the transmitter achieves an efficiency of 56% at full power (40 dBm under QPSK modulation), and 35% at 18 dB in back-off. The third-order IMDs for a two-tone signal vary from -30 dBc to -40 dBc over a 20 dB back-off range.

High peak power dielectric resonator oscillator combiner

The author describes an approach that achieves significant amounts of peak power from an oscillator, dielectrically stabilized, and power combined, in one stage. The active elements used were stacked Gunn diodes operating in X- and Ku-bands. 40 W and 112 W of peak power were measured from two-diode and four-diode DRO/combiners respectively, operating in X-band (9.3 GHz), and 13.5 W of peak power was measured from a two-diode DRO/combiner in Ku-band (16.3 GHz). The approach presented makes possible the production of sources with fewer active devices, and reduces the number of circulators and isolators needed to achieve the same amount of output power (versus the conventional approach of using a low-level DRO followed by a cascade of amplifier/power combiner stages).<<ETX>>

Passive stabilization of sources using a dielectric resonator and a modified ring hybrid

An approach to the frequency stabilization of sources, high power or low, vacuum tube or solid-state, is described. The method uses a high-Q dielectric resonator coupled to a three-arm ring hybrid. Stabilization factors of three-arm ring hybrid. Stabilization factors of three to five have been successfully achieved (in X- and Ku-bands) with pulsed magnetrons over an operating temperature range of -55 degrees C to +95 degrees C, and stabilization factors of 2 to 24 have been successfully achieved with X- and Ku-band pulsed IMPATT (impact avalanche and transit time) oscillators, some, but not all, operating over temperature ranges of -46 degrees C to +80 degrees C.<<ETX>>

A Multi-Diode Cavity Power Combiner Using State-of-the-Art Pulsed Gunn Diodes

Large area mesa pulsed Gunn diodes were developed. These diodes generated 30 to 40 watts per device. By combining multiples of these diodes in a miniature C-band cavity power combiner, 90 watts (3-diode combiner) and 150 watts (5-diode combiner) of peak power was achieved.