High efficiency switching power amplifiers for multi-band radar

Abstract

The reduction of size, weight, power, and cost (SWaP-C) of radio frequency (RF) components is becoming increasingly important to meet industry requirements. In meeting the SWaP-C objectives, RF components will be required to be smaller and more power efficient than the current state- of- the- art while sustaining high performance functionality. In compliance with SWaP-C and high performance functionality is a High Efficiency Switching Power Amplifier. This study focuses on the more efficient breed of switching power amplifiers (PAs), particularly the Class F PA with new techniques to operate broadband on multiple radar bands. Efficiencies in the range of 60% to 80% for Class F PAs have been reported in literature; however, this efficiency is only attainable over narrow bandwidths on the order of 10%. Several innovative techniques have been identified to increase the efficiency and operational bandwidth of RF power amplifiers (PAs) for radar applications. The amplifier design also incorporates fast turn on and turn off circuits to achieve switching times of less than one microsecond (μs). This enables the PA to be switched off during the receive period to prevent self-generated noise from corrupting the received signal. Also, high-power transmit and receive (T/R) switches at the antenna feed can be eliminated. A wideband PA enables the design of a multi-band radar, reducing the number of components needed for operation in the L and X bands. A high efficiency PA is also key to reducing battery size and cooling requirements in radar applications.