Real-time configurable RF matching networks for pulse-based systems
Abstract
In this work, a time-domain technique of impedance matching specifically designed for pulse-based transceiver systems is developed. The proposed time-varying matching networks are configurable in real-time and achieve exceptional performances by exploiting the time-domain characteristics of the pulse signals of interest. Depending on the information that is available about the pulse signals, different matching schemes are developed in different applications. In the transmitting systems, with the known information about the pulses including the shape, timing and magnitude, a time-varying matching network is designed to pre-store energy in critical reactive components to set up proper initial conditions for each incoming pulse. As a result, it significantly improves the gain-bandwidth performance that is one of the major limitations of conventional matching networks. The performance of this time-varying design is demonstrated in matching a 50-Ohm source to different resistive, RC and RL loads. In the receiving systems where the only information available is the pulse timing and synchronization, a real-time configurable matching design is developed without using pre-biasing. It has the ability to efficiently capture the energy from a high-Q source within each pulse duration and deliver it to the load expeditiously after the pulse ends. This technique is applied to the matching circuit design for electrically small antennas receiving wideband pulse signals. Simulation and measurement results show that an exceptional pulse compression effect can be obtained. Specifically, the received pulse after the matching network features a large amplitude, narrow duration and a shape that is not dependent on the incoming pulse. It is also shown that the proposed design is promising for working in multipath environments and has the ability to discriminate closely aligned pulses. The noise performance of the proposed matching network is also analyzed and measured, with results showing that considerable improvement in the instantaneous signal-to-noise ratio can be achieved compared to the conventional matching design.
Degree
Ph.D.
Advisors
Katehi, Purdue University.
Subject Area
Electrical engineering
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