Effect of substrate temperature dependence on six-port reflectometer performance

This paper first investigates the effect of substrate temperature dependence on performances of six-port reflectometer (SPR) designed for measuring complexity permittivity. The temperature-dependent effect on the substrate is described by the variation of dielectric constant (έ_r) and dissipation factor (tanδ). Here, two printed circuit boards (RO3003^® and RO3010^®) with two different substrate materials are used for designing the SPRs operating at 4 GHz. The accuracy of these SPRs to predict moisture content in rubber latex over a certain temperature range will be studied. The obtained results indicate that the temperature dependent of the substrate has an impact on the SPR performances.

I. Introduction

Six-port reflectometer (SPR) is one of the various applications of six-port measurement circuit [1]. The SPR is widely used for determine the complex reflection coefficient of the device under test (DUT) to predict the DUT properties for its low complexity in hardware as illustrated in Fig. 1 [2]. The removal of non-ideality caused by hardware can simply be manipulated by calibration either in manual or automatic way. Fig. 1 SPR structure