Lynch-Ayers microwave dielectric loss bridge for use over a range of temperatures

Precision measurements of losses in low-loss liquid dielectrics at microwave frequencies may be performed by means of a bridge method described by Lynch and Ayers. The paper describes modifications to such a bridge in order that measurements may be made over a range of temperatures. Results are presented for the temperature variation of loss angle at X-band in two very low-loss materials (cyclohexane and cycloheptane). The errors arising in the measurements are analysed; the overall likely error in the determination being ±(1¿rad or 2.4%).