Studies on Mn-doped barium nanotitanate dielectric resonators

Abstract

The use of dielectric resonators for various applications in microwave and millimetre wave range is (6) growing rapidly. In order to fabricate efficient devices using dielectric resonators it is of vital importance to develop suitable materials and to study the dependence of different material properties (4) on the overall performance of the device. There has been considerable progress in using cylindrical dielectric resonators whose dominant modes are of TE01«+o type. The resonator can be excited easily in this mode by placing it adjacent to a microstrip line. As this configuration has many applications in microwave integrated circuits (MIC), it is of great importance to investigate how the (5) fundamental modes depend on the material properties and resonator dimensions. The material used in dielectric resonators should have high dielectric constant, of the order of 40, and temperature coefficient (rf) less than 5 ppm°C -1 and Q of the order of 5000 or higher. Research for developing such materials has been carried out intensively all over the world. Since the first demonstration by Ritchmayer in 1939 [1]. Barium nanotitanate is widely used as a dielectric resonator material. It has been shown that the addition of Mn improves the electrical characteristics of dielectric resonators [2]. In this letter we report the result of the Mn doping on the performance of a cylindrical dielectric resonator. In order to identify the different modes and to compare the validity of the results the resonant frequency was calculated using the approximate method proposed by Roh and Rudokas [3]. with The method is very useful for calculating fundamental TE01/+a modes in comparison with rigorous analytical methods such as the integral equation and method, mode matching method etc. [4]. We also calculated the Q values due to the losses at the conductor in an idealized case, as shown in Fig. 1. We present the calculation of resonant frequencies of fundamental TE01/+~ modes using the approximation of Roh and Rudokas [3]. Accordingly most of the electromagnetic energy is confined to the geometric boundary of the dielectric resonator itself