In this paper, we develop a bandpass filter using a stub-loaded stepped impedance resonator (SLSIR) and calculate the even and odd resonant modes of this type of resonator using the input impedance/admittance analysis. In this study, two impedance ratios and two length ratios are operated as the design parameters for controlling the resonant modes of the SLSIR. Several resonant mode variation curves operating three resonant modes with different impedance ratios and two length ratios are developed. By tuning the desired impedance ratios and length ratios of the SLSIRs, compact ultra-wideband (UWB) bandpass filters (BPFs) can be achieved. Two examples of the UWB BPFs are designed in this study. The first example is UWB filter with a wide stopband and the second one is dual UWB BPF, namely, with UWB performance and a notch band. The first filter is designed for a UWB response from 3.1 to 5.26 GHz having a stopband from 5.3 to 11 GHz, with an attenuation level better than 18 dB. The second filter example is a dual UWB BPF with the frequency range from 3.1 to 5 GHz and 6 to 10.1 GHz using two sets of the proposed SLSIR. The measured results have insertion loss of less than 1 dB, and return loss greater than 10 dB. Furthermore, the coupling structures and open stub of the SLSIR also provide several transmission zeros at the skirt of the passbands for improving the passband selectivity.

In this paper, we propose the new compact multilayer quint-passband bandpass filter. The multilayer substrate technique is used for further miniaturizing the circuit size. The filter has quint passband at 1.8, 2.5, 3.3, 3.8 and 4.5 GHz. Coupled resonators such as the stepped impedance resonators (SIRs), stub-loaded uniform impedance resonators (UIRs), and quarter-wavelength uniform impedance resonators are applied to produce the quint-passband of the filter simultaneously. The stub-loaded uniform impedance resonators and stepped impedance resonators can easily obtain a filter with closed passbands. Using a multilayer substrate technique, the filter can provide multipath propagation to improve the frequency response and achieve a compact circuit size. The proposed quint-passband bandpass filter shows a simple configuration, a practical design method, and a small circuit size.

A high-efficiency biochip for screening circulating tumor cells is proposed by using circulating tumor cells screening biochip using the nanocrystalline silicon (nc-Si:H) thin film prepared by 40.68-MHz very high-frequency plasma-enhanced chemical vapor deposition (VHFPECVD) is proposed. The quality, uniformity, and electrical properties of the prepared nc-Si:H thin films affect the performance parameters of the biochip, such as its recovery rate, purity, and survival rate, for screening circulating tumor cells. By applying different chamber pressures of 600, 800, and 1000 mTorr, during 40.68-MHz VHFPECVD, the highquality nc-Si:H thin film with a surface roughness of 10.9 nm, a resistivity of 3.3 × 101 Ω-cm, and an absorption coefficient of 104 cm-1 was obtained. The proposed circulating tumor cells screening biochip exhibited a recovery rate of 76%, purity of 82%, and survival rate of 88%. The screening performance of the biochip is highly associated with the quality of the deposited nc-Si:H thin films; therefore, the selection of an appropriate deposition technique is crucial for applications in a clinical trial.

We present to depositing passivation layers a-Si:H thin films on the top and bottom of the n-type crystalline silicon by different process parameters using very high frequency (VHF, 40.68 MHz) plasma-enhanced chemical vapor deposition (PECVD). Comparing furnace annealing furnace with microwave annealing (MWA) we obtain excellent passivation efficacy can in significantly faster of annealing in semiconductor processing.

This paper proposes the effects of chamber pressures on the passivation layer of hydrogenated nano-crystalline silicon (nc-Si:H) mixed-phase thin film using microwave annealing (MWA) to achieve a high-quality thin film. The use of 40.68 MHz very-high-frequency plasma-enhanced chemical vapor deposition (VHFPECVD) deposited the nc-Si:H mixed-phase thin film on the top and bottom of the n-type crystalline silicon substrate. The chamber pressures (0.2, 0.4, 0.6, and 0.8 Torr) of the VHFPECVD were critical factors in controlling the carrier lifetime of the symmetric structure. By using the VHFPECVD to deposit the nc-Si:H and using the MWA to enhance the quality of the symmetric structure, the deposited nc-Si:H’s properties of a crystalline volume fraction of 29.6%, an optical bandgap of 1.744 eV, and a carrier lifetime of 2942.36 μs were well achieved, and could be valuable in thin-film solar-cell applications.