Swept frequency gain measurements for standard horn antennas

This paper describes a swept frequency gain measurement technique for standard horn antennas based on the three-antenna method. The method uses a swept frequency source, a VNA based mismatch evaluation and an averaging process with uniform steps of separation distance for minimizing mutual antenna reflections and results in a similar uncertainty level to the single frequency measurements.

Introduction

National Measurement Institute Australia has been calibrating standard horn antennas at single frequencies using the three-antenna method in a radio anechoic chamber for a number of years [1]. The gain of a horn antenna is determined by measuring the transmission loss versus separation distance between two horns. A theoretical factor is then used to correct the near field errors.