Study of Multiband Bandpass Filter

• Main Author: 徐子祥
• Other Authors: 尤正祺
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/68189032966925993169

碩士 === 逢甲大學 === 通訊工程學系 === 101 === In this paper, a multi-band filter as the research subject, are three small size, simple structure, and low cost bandpass filters, are applicable to wireless local area networks (WLAN) and the worldwide interoperability for microwave access (WiMAX). In addition to develop can be individually applied to GSM1800 (1.71-1.88 GHz) band in the four band pass filter, and implemented in 0.8 mm thickness, dielectric coefficient is 4.4 on the FR4 substrate. First introduced for dual-band bandpass filter, using twoλ/2 stepped impedance resonators to design, through the impedance change of stepped impedance resonators and the ratio of electrical length to adjust, the design frequency required band, the center frequency of the bandpass filter is 2.68 GHz and 5.27 GHz, the main size only 20.4 x 12.5 mm2. The experimental results show, the filter with WLAN (5200 MHz) and WiMAX (2700/5500 MHz) of the band. Next, a tri-band bandpass filter, the use of three asymmetric stepped-impedance resonators to design, the bandpass filter with the center frequency of three bands is 2.41 GHz, 3.6 GHZ, 5.86 GHz, the filter main size only 22.2 x 29.8 mm2. The experimental results show, the filter with WLAN (2400/5800 MHz) and WiMAX (2500/3500/5500MHz) of the band. Finally, a quad-band bandpass filter, the use of asymmetric stepped-impedance resonators to design, the quad-band bandpass filter architecture is divided into two parts, one part is designed to operate at the first and third passbands (1.85/3.75 GHz), the other part design and operation in the second and fourth passbands (2.75/5.25, GHz) by impedance adjusting asymmetric stepped-impedance resonator ratio and electrical length ratio, a four band pass filter can be designed, the experimental results show that, the filter with GSM1800 ( 1.71-1.88 GHz ), WLAN ( 5200 MHz ) and WiMAX ( 2700/3600MHz ) of the band. The three bandpass filter is proposed in this paper, the measurement and simulation are in good agreement, related to products can therefore be used for wireless communication.