| Summary: | 碩士 === 國立彰化師範大學 === 電子工程學系 === 101 === The objective of this thesis is to design three bandpass filters (BPF) by using TSMC 0.18-µm CMOS 1P6M mixed-mode technology. The operating bands of the designed BPFs are located in super-high frequency (SHF) band.
In the first circuit, a tunable transmission zero in the upper stopband of the designed BPF is created by a circuit block consisting of a CMOS FET switcher, a negative resistance, and an LC tank. This design could be applied in Ku microwave band (12-18 GHz). The measured results of the S-parameter (|S21| and |S11|) show that, the minimum insertion loss of the passband is 2.52 dB and the maximum return loss is 25.28 dB. In addition, the two transmission zeros at 5.38 and 26.02 GHz, which being around the lower and upper passband edges, respectively, are tunable.
In the second BPF circuit, an ultra-wideband (UWB) bandpass filter (BPF) was designed. It has three finite transmission zeros at high frequency region to obtain a wide upper stopband. The three transmission zeros can be controlled by circuit elements and locate around 22.43, 29.49, and 46.39 GHz, respectively. The upper stopband has an insertion of larger than 20 dB over the frequency of 15.11–67 GHz. In the circuit design, the inductors are spiral inductor type which is implemented by using microstrip line for obtaining low noise. Additionally, the capacitors are used metal-insulator-metal (MIM) capacitors for obtaining large capacitance. The measured minimum insertion loss of the designed UWB BPF is 2.01 dB and the passband is 1.71–11.7 GHz. The return loss is around 10 dB over the frequency range of 2.196–10.6 GHz.
In the third circuit, we present a dual-band bandpass filter. The bandwidth of the upper passband is controlled by varactors. Simulated results show that the designed BPF can achieve a lower passband of 3.3–6.5 GHz with a minimum insertion loss of 2.7 dB and a minimum return loss of 22.65 dB. The varactor-induced transmission zero can be varied from 41.4 to 50.36 GHz, leading to a tunable upper passband from a range of 20–28.83 GHz to 20–37.43 GHz, with a minimum insertion loss of around 3.41 dB and a minimum return loss of 31 dB.
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