| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 98 === This thesis uses two new guide-wave structures to develop microwave and millimeter-wave circuits. For the microwave circuit design, the slot-coupled microstrip lines are employed to implement Marchand balun and doubly balanced mixer. For the millimeter-wave circuit design, the complementary-conducting strip(CCS) lines are utilized to realize millimeter-wave bandpass filters. The circuit design concepts, fabrications, and experimental results are presented in the thesis.
For the microwave circuit design, diamond-shape slot-coupled microstrip lines are used to design broadband microwave circuits. Since this guided-wave structure can provide a high ratio of even-mode and odd-mode impedances and flat phase response, these properties are applied to design a broadband Marchand balun with a flat phase response. The developed baluns are then exploited to realize a doubly balanced mixer. Based on the simulated and measured results, the developed Marchand balun has a 90% relative bandwidth. The in-band phase and amplitude im-balances are in the range of -180.4o~181.8o and -0.37 dB~0.32 dB, respectively. The developed doubly balanced mixer has a conversion loss better than -10 dB from 1.2 GHz to 4 GHz as the intermediate frequency is set to 100 MHz.
For the millimeter-wave circuit design, this thesis uses low loss and slow-wave structures, CCS lines, to realize compact dual-mode ring bandpass filters. The open-stub and step-impedance perturbation structures are inserted into the ring resonators for dual-mode excitation. The developed filters with open-stub perturbations occupy chip sizes of 330 mmx240 mm, while those with single and double step-impedance perturbations have 372 mmx 180mm and 360 mmx 210 mm chip sizes, respectively, Since the filters with step-impedance perturbations have symmetrical structures and low discontinuity effects, they can achieve lower insertion losses at center frequency around 60 GHz. The experimental results demonstrate that using CCS line can effectively reduce chip sizes of CMOS passive components and retain original circuit characteristics.
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