Antenna-Pattern Measurement Using Spectrum Analyzer for Systems with Frequency Translation [Measurements Corner]

Pattern measurements using a network analyzer are typically based on measuring the transmission coefficient, S₂₁. When the transmitting and receiving frequencies are different, it is not possible to directly measure the antenna pattern using a network analyzer. In this paper, an antenna-pattern measurement system using a spectrum analyzer, designed to measure the radiation pattern of an antenna with a microwave sampling beamformer (MSBF) structure, is presented. A synthesized oscillator was used as the transmitter in the measurement setup. The instruments were controlled through GPIB by a program specifically designed for the system. High-quality pattern measurements were obtained for several antenna types. The measurement results were verified using HFSS simulations.