Design Of Antenna Switch Module Based On LTCC Technology

With the dramatically development of mobile communications, there are growing demands on mobile terminals for high performance, low cost, and compact size, multi-functional, digital and high reliability and on components for miniaturization, integrated, modular. Recently, the development of LTCC (Low Temperature Co-fired Ceramic, LTCC) technology provides a powerful impetus for the RF front-end modular mobile phone. The multi-dimensional wiring characteristics and excellent electronic, mechanical, thermal properties of LTCC technology are becoming the first choice for the RF front-end modular mobile phone.This paper is based on LTCC technology to design GSM/DCS dual-band antenna switch module and GSM/UMTS multi-band antenna switch module. Specific work and research as follows:1,Low-pass filter design. A GSM850/900MHz low-pass filter, which size is 2.0mm×1.2mm×1.0mm, is designed based on lumped circuit model. To enhance the second and third harmonic suppression, there are two transmission zeros introduced by the LC resonator. In the 3D modeling process, make full use of parasitic capacitance to reduce the number of stack.2,Diplexer design. In order to reduce the circuit's complexity and save the area, the matching network is removed by the filter complementary method. Transmission zeros introduced by the LC resonator and cascade aπ-type low-pass filter behind of the high-pass filter are adopted to enhance the harmonic suppression. Finally, an excellent performance diplexer ,with the pass band of 859±35MHZ and 1920±70MHz, is designed. The chip size is 2.0 mm×1.2 mm×1.0 mm.3,GSM/DCS dual-band antenna switch module design. Dual-band antenna switch module is composed of diplexer, SPDT and low-pass filter. This paper analyses of how to broken down the overall technical indicators into individual components and focuses on designing of SPDT. A GSM/DCS dual-band antenna switch module is designed and optimized based on co-simulate of Agilent ADS and Ansoft HFSS. The whole size of the module is 3.2mm×3.2mm×1.4mm. In GSM and DCS transmit mode,the pass band insertion loss is respectively 1.2dB and 1.8dB, the second and third harmonic suppression are both greater than 30dB, the rest of the performance meets all the specifications.4,GSM/UMTS multi-band antenna switch module design and production. The module, which size is 2.5mm×2.5mm×1.15mm, mainly consists of a SP9T microwave switch and two low pass filters embedded in LTCC substrate. This paper focuses on LTCC substrate and the integration of the SP9T switch and the LTCC substrate. Finally based on co-simulation of ADS and HFSS, the integration of the SP9T switch and the LTCC substrate is implemented, and the module is optimized in ADS. The simulation results of the module showed that it has good performance. At last, the ceramic substrate is product and test.