Performance Evaluation for Bi-directional Optical Fiber Link Transceiver for Antenna Measurement From 1 to 6 GHz

We have already developed an antenna measurement system using bi-directional radio over fiber transceiver system from 1 GHz to 6 GHz. Our proposed system consists of bi-directional optical fiber link transceiver with microwave directional coupler that can extend the port of vector network analyzer. Our proposed system can measure S-parameters in full 2-port calibration from 1 to 6 GHz with less than 0.1 dB linearity for 40 dB attenuation measurement of vector network analyzer. In this paper, we show some advantage for antenna transmission coefficient and reflection coefficient measurement that compare with using our proposed system and using coaxial cable results for double ridged guide horn antenna from 1 to 6 GHz.

I. Introduction

We have already developed a bi-directional type optical fiber link system for vector network analyzer (VNA) up to 6 GHz [1][2]. Our proposed system Our proposed system consists of two bi-directional optical fiber link transceivers with microwave directional coupler for antenna under test, two bi-directional optical fiber link transceivers for VNA and two single mode optical fibers. Our system can measure s-parameter in full 2-port calibration. For calibrating antenna gain, we usually use 3-antenna extrapolation technique [3] with accurate measurement condition. For this reason, we evaluate our proposed system performance for antenna transmission coefficient and transmission coefficient measurement.