Design of Bandpass Filter and Oscillator Using Substrate-Integrated-Waveguide
Date Issued
2005
Date
2005
Author(s)
Chen, Kuo-Hao
DOI
zh-TW
Abstract
Microwave filters and oscillators are key components in wired or wireless communication systems. With the increasing wireless communication applications, the frequency band below 5 GHz become more and more intensive. Therefore, the research and development of components and technology in the higher frequency bands are essential to meet the needs of wireless communication. In the higher frequency design, problems require more efforts to overcome, such as circuit losses, difficulties of manufacturing, and measurement. In order to reduce the filter loss and oscillator phase noise, substrate integrated waveguide (SIW) is selected in this study
instead of other transmission lines.
In this thesis, three types of bandpass filters and four types of oscillators are designed with the use of SIW cavity. For the first kind of filter, a LTCC SIW cavity filter operated from 40 GHz to 48 GHz is designed. Its feeding structure is like the probe excitation using coaxial line. The lowest measured insertion loss is 1.173 dB and return loss is higher than 7 dB. For the second kind of filter, a LTCC dual-mode SIW cavity filter at 30 GHz is designed. Its feeding structure uses a current loop excitation integrated with a transition circuit for the probe measurement. Two orthogonal modes are designed to be excited in a single cavity without any perturbation of coupling vias or square corner cutting. The lowest measured insertion loss is 2.211 dB at 30.85 GHz, the return loss is higher than 15 dB, and the 3-dB bandwidth centered at 30.85 GHz is about 5.4%. The two transmission zeroes outside the passband are located at 27.6 and 32.45 GHz with insertion loss higher than 33 dB. For the third kind of filter, a bandpass filter at 60.5 GHz is designed with cascading two dual-mode SIW cavities. TE102 mode and TE301 mode are excited in one cavity to yield a transmission zero located at the left side of passband, whereas TE102 mode and TE201 mode are excited in the other cavity to yield the other transmission zero at the right side of passband.
For oscillators, all of them are designed using parallel feedback structure. With the feedback of a circular SIW cavity, the first oscillator is measured to give 1.434 dBm output power at 11.79 GHz and phase noise of -92.72 dBc/Hz at 100 kHz offset from the carrier. The second oscillator using a rectangular SIW cavity is measured to give 2.271 dBm output power at 11.79 GHz and phase noise of -85.23 dBc/Hz at 100 kHz offset from the carrier. The third oscillator with the use of half-wavelength microstrip line resonator is measured to give 3.826 dBm output power at 12.12 GHz and phase noise of -75.31 dBc/Hz at 100 kHz offset from the carrier. The fourth oscillator with the use of a rectangular SIW cavity is measured to give 4.274 dBm output power at 9.94 GHz and phase noise of -100.8 dBc/Hz at 100 kHz offset from the carrier. Finally, the measured results of three bandpass filters and four oscillators are summarized in a table. All the findings and studies of this thesis on the implementation of SIW passive and active devices in the microwave and millimeter-wave ranges may have the potential in the applications of communication systems.
Subjects
帶通濾波器
振盪器
bandpass filter
oscillator
Type
thesis
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