Measurement of Radar Spurious Emission With High Dynamic Range and Optimized Measurement Time

The purpose of this paper is to propose and analyze a novel field-capable method for measuring the spurious emission levels of weather radar. The method consists of time- and frequency-domain measurements. The time-domain measurements determine radar parameters, such as pulse duration, duty cycle, pulse repetition rate, and antenna rotation time; these are then used in the frequency-domain sweep measurements to obtain the relative level of radar spurious emissions in a given bandwidth with a minimum measurement time for a given average percentage of measured bandwidth. A large dynamic range (≥100 dB) is obtained by using a calibrated bandstop (BS) filter for controlled attenuation of the pulse spectrum at the nominal frequency. Results are shown for commercial weather radar at 5 GHz. This paper shows the need for radar signal filtering to prevent interference with other radio systems, such as radio local access network (RLAN) worldwide interoperability for microwave access (WiMAX), ultrawideband (UWB), and terrestrial radio relay systems, particularly those operating just above or below the nominal frequency of radar. The results give important information for radar system planning and communication network operations.