The effects of phased-array antennas on the performance of wideband LFM radars

摘要

In many modern applications, radars are required to detect and track multiple targets at long ranges with very good range and angle accuracy The combination of these requirements can be met by the use of high transmitter power, wideband linear frequency modulated (LFM) waveforms, and electrically large phased-array antennas. In order to support the high power and wideband waveforms, the phased-array antenna is broken into subarrays, each with a time delay unit (TDU) and final power amplifier. The use of wideband LFM pulses causes significant problems in terms of frequency dispersion if the antenna is a phased array. The effects of wideband LFM signal processing in phased array radars have been documented in the past [1]. Further work was performed [2] which addressed the particular issues associated with a subarrayed phased-array antenna as might be required in a wide bandwidth, high gain system. In addition to the performance issues of dispersion loss, compressed pulse widths, and grating lobes, the use of quantized TDU's causes a degradation of the null depth in monopulse systems.