Millimeter-Wave Single-Post Dual-Mode Cavity Filter and 3-D LTCC Dual-Mode Ring Filter
Date Issued
2004
Date
2004
Author(s)
Tsai, Ming-Lung
DOI
zh-TW
Abstract
Abstract
Microwave filters play an important role on wire and wireless RF/Microwave system applications. For the commercial applications, the filter requirements such as small size, low cost, narrow bandwidth and high quality factors become more and more stringent. In this thesis, two structures of filters suitable for millimeter-wave application are analyzed and implemented on printed circuit boards (PCB) and low-temperature co-fired ceramics (LTCC) process. The filter design theory, design procedure, and frequency response are discussed in detail.
The first structure is the single-post dual-mode cavity filter using the substrate integrated waveguide (SIW) techniques. This thesis proposes a new cavity filter structure by introducing the single-post in the cavity resonator. The coupling-post can generate the two coupled resonator modes, which results in two transmission zeros in the filter responses. It has an excellent out-of-band rejection. The SIW filter is designed on Ka-band and measured with 1.6 dB insertion loss, 15 dB return loss, and 4.8% bandwidth. The relations between the insertion loss, return loss and transmission zeros location verse the post location are discussed.
The second structure is the 3-D LTCC dual-mode ring filter. In recent years, most dual-mode ring filters are using the planar structures. In this thesis, we propose a new coupling structure to implement dual-mode ring filter on the multi-layer PCB or LTCC process. The feeding signal port and the ring resonator are separated into two different layers. The broadside-coupling structures between the two layers with couple the feeding signal to the ring resonator. Adjusting the overlapped area of broadside-coupling structures, a specific coupling factor at the feeding ports can be easily achieved. The size of 3-D ring filter is smaller than the ring filter using planar structures. Finally, we compare the characteristics of above two filters, and study their feasibility for MMW applications.
Subjects
微波濾波器
共振腔
雙模濾波器
Cavity
Microwave Filter
Dual-Mode Filter
Type
thesis
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