유전체 공진기를 이용한 이동통신 단말기용 듀플렉서 필터 설계

Abstract

본 논문에서는 고유전율을 갖는 유전체 세라믹 재료를 이용하여 유전체 공진기 듀플렉서 필터를 설계 하였다. 기존의 듀플렉서 필터는 송신 3차, 수신 4차로 각 공진기를 횡으로 배열하는 구조를 갖는다. 본 논문에서는 송수신단 공진기를 수직으로 배열한 구조로 설계 하였다. 송신단과 수신단을 동일한 4차 필터로 구현하여 송신단에서 충분한 감쇠를 얻을 수 있었으며, 송·수신단에서의 통과대역은 각각 1.750-1.780GHz, 1.840-1.870GHz로 30MHz의 대역폭을 가지며 각 단에서의 신호의 분리도는 약 34dB 이상이며, 부피는 16㎜ ×6.77㎜ ×4㎜로 0.433㏄로 상용화된 필터의 약 90.2%로 설계 하였다. 각각의 유전체 공진기는 원형 동축형을 사용 하였으며, 제작공정의 단순화를 위해 각 공진기의 내·외경을 동일하게 하고 각 공진기의 공진 주파수는 공진기의 길이를 조절해 휴대전화 대역에 적합한 구조와 특성을 갖도록 설계 하였다.

In this paper, a duplexer filter for mobile communication is designed using dielectric resonators with high dielectric constant ceramic materials. A commercial duplexer filter for mobile communication handy set is consist of horizontal array, and each sections of duplexer have 3 pole for Tx and 4 pole for Rx. In this paper, the designed filter have the structure of vertical array, and each sections of Tx and Rx have 4 pole. As a results, Tx sections have enough attenuations at Tx stopband frequencies. The passband of each sections; Tx, Rx, are 1.750-1.780GHz, 1.840-1.870GHz, so have 30MHz bandwidth, and the isolations between Tx and Rx bands are more than about 34dB. The physical size of designed duplexer filter is 16㎜ ×6.77㎜ ×4㎜, equals 0.433㏄, and it is about 90.2% of commercial filter size. Each dielectric resonators are designed by stepped impedance resonators with equal size of inside and outside diameters for simple fabrications. The resonant frequencies of each resonators are tuned by each resonator length, and the structure and characteristics are well suited for PCS(Personal Communication Systems) service.

In this paper, a duplexer filter for mobile communication is designed using dielectric resonators with high dielectric constant ceramic materials. A commercial duplexer filter for mobile communication handy set is consist of horizontal array, and each sections of duplexer have 3 pole for Tx and 4 pole for Rx. In this paper, the designed filter have the structure of vertical array, and each sections of Tx and Rx have 4 pole. As a results, Tx sections have enough attenuations at Tx stopband frequencies. The passband of each sections; Tx, Rx, are 1.750-1.780GHz, 1.840-1.870GHz, so have 30MHz bandwidth, and the isolations between Tx and Rx bands are more than about 34dB. The physical size of designed duplexer filter is 16㎜ ×6.77㎜ ×4㎜, equals 0.433㏄, and it is about 90.2% of commercial filter size. Each dielectric resonators are designed by stepped impedance resonators with equal size of inside and outside diameters for simple fabrications. The resonant frequencies of each resonators are tuned by each resonator length, and the structure and characteristics are well suited for PCS(Personal Communication Systems) service.