A Compact, High-Gain, High-Power, Ultrawideband Microwave Pulse Compressor Using Time-Reversal Techniques

Generation of high-peak-power, microwave ultrashort pulses (USPs) is desirable for ultrawideband communications and radar/remote sensing. A variety of microwave USP generators exist today, or are described in the literature, and have benefits and limitations depending on the application. A new class of pulse compressors for generating USPs using electromagnetic time-reversal (TR) techniques has been developed in the last decade and is the topic of this article. This article presents a compact TR microwave pulse-compression cavity that has ultrawide bandwidth (BW) (5-18 GHz) and employs waveguide feeds for high-peak-power output over the entire band. The system uses a time-reversal-based pulse compression scheme with one-bit processing (OBTR) to achieve high-peak power. We present results from full-wave simulations and measurements showing compression gain exceeding 21.2 dB, 22% efficiency, and measured instantaneous peak output powers reaching 39.2 kW. These are all record results for this type of pulse compressor. In addition, we present a new analysis of variation in compression gain due to impulse response recording time and BW variation, new experimental work on the effect of mode stirrer position on compression gain, and a novel RF switch-based technique for reducing time-sidelobes while using OBTR.