Cheng Yuan Hung

Design of a Wide-Stopband Bandpass Filter by Using Different Feeding Positions of the I/O Ports

In this paper, a wide-stopband bandpass filter is presented. The proposed filter only used two stepped-impedance resonators (SIRs) with a simple electric-coupling structure to accomplish a wide-stopband response. The passband of the proposed filter is designed for global system for mobile communications (GSM) at 1.8 GHz. The spurious responses of the SIRs are suppressed by controlling the locations of the transmission zeros effectively. The measured results show the passband at 1.8 GHz with a low insertion loss 1.18 dB, and the 3 dB fractional bandwidth (FBW) of 14.1%. The rejection of the stopband is greater than 14 dB from 2.1 to 17.7 GHz, a stopband bandwidth of 9.8 times of the fundamental frequency. The measured result of the fabricated filter also shows a good agreement with the simulated result.

Design of the Fractal-Based Dual-Mode Bandpass Filter on Ultra Thin Liquid-Crystal-Polymer Substrate

In this paper, a novel miniature dual-mode bandpass filter based on modified Sierpinski fractal is proposed and realized on the ultra thin (100 μm) flexible liquid-crystal-polymer (LCP) substrate for wireless local area network (WLAN) IEEE 802.11a. The subwavelength property which leads to the miniature characteristic is investigated in this paper. We adopt the 3rd order Sierpinski geometry as the mainly dual-mode resonator to form a dual-mode filter. The measured result is in good agreement with the full-wave simulation result.

Design of a Compact Ultra-Wideband Bandpass Filter With an Extremely Broad Stopband Region

This letter presents a design of a compact ultra-wideband (UWB) bandpass filter (BPF), which can exhibit an UWB response from 3.1 to 9.9 GHz with low insertion loss (IL) of 0.8 dB and an extremely broad stopband region from 10.9 to 25.1 GHz with high rejection level of 20 dB. This UWB BPF is simply constructed by using only one single-stage parallel-coupled line and two rectangular stub resonators. In this design, the rectangular stub resonators provide an exciting mode to enhance the desired UWB response and also create tunable transmission zeros to extend a wide stopband by controlling the impedance ratio (R) properly. The filter was fabricated and measured to verify the design concept.

Design of a Dual-band Bandpass Filter for GSM and Direct Sequence Ultra-wideband Communication Systems

In this paper, the design of a dual-band bandpass filter (BPF) with narrow- and wide-band performances simultaneously is presented. The proposed filter only uses two stepped-impedance resonators (SIRs) to achieve the narrow- and wide-band performances. Moreover, transmission zeros are created near the passband edges to improve the band selectivity and can be controlled easily by arranging the coupling structures. A filter example is designed and implemented for global system for mobile communications (GSM) at 1.8 GHz and lower passband of the direct sequence ultra-wideband systems (DS-UWB) at 3–5 GHz. The measured results of the fabricated filter confirm the concepts of the proposed design and match the simulated results.

Design of a high band-isolation diplexer based on asymmetric stepped-impedance resonators with side-coupling structure

In this paper, a high band-isolation diplexer based on two bandpass filters (BPFs) formed using asymmetric stepped-impedance resonators is presented. The passbands of the diplexer are operated at 1.8 GHz for global system for mobile communications (GSM) and 2.4 GHz for wireless local area network (WLAN). Side-coupling structure is adopted in BPFs to create two additional transmission zeros, thus enhancing the band isolation and stopband region. The measured results of the proposed diplexer show the passband at 1.8 GHz with a low insertion loss of 1.09 dB, a 3 dB fractional bandwidth (FBW) of 9.4% in the first channel and a passband at 2.4 GHz with an insertion loss of 2.6 dB, a 3 dB FBW of 6.2% in the second channel. The measured results of the fabricated diplexer also show a good agreement with the simulated ones.

Design of an Ultra-Wideband Bandpass Filter by Using Coupled Three Line Microstrip Structure

Abstract In this paper, an ultra-wideband bandpass filter was accomplished. The proposed filter is constructed by using a coupled three line microstrip structure and a stepped-impedance open stub (SIOS), connected at the symmetrical plane of the filter to increase the passband selectivity. The measured result shows the centered frequency of the passband at 3.97 GHz with low insertion loss of 0.48 dB and wide 3-dB fractional bandwidth (FBW) of 45.3% from 3.1 GHz to 4.9 GHz. Two transmission zeros are obtained near the passband at 2.72 GHz and 5.71 GHz with good rejection level of 50.3 dB and 60.5 dB, respectively. The measured results of the fabricated ultra-wideband bandpass filter also show a good agreement with the simulated ones.

High efficiency transparent digital television antenna based on nano-structured thin film coating technology

In this paper, we proposed the high transparent digital television (DTV) antenna. The used transparent material is based on nano-structured thin film coating on the glass substrate for achieving the transparency up to 80%. The substrate dimension size of the proposed design is 200 × 150 mm2. The proposed antenna has radiation efficiency of 66.52% and having the bandwidth of 0.46–0.66 GHz. The proposed antenna is very much compatible to digital television signal receiving applications.

A new high transmittance dipole antenna

We proposed the new high conductivity material for developing the high transparent dipole antenna. The proposed material is based on the nano-structured thin film and deposited on the glass substrate. Our invented activation process is used to rearrange the direction of nano-structure inside the thin film from disorder to order arrangements. The transmittance of antenna can be achieved to 80%. The overall dimension size of the antenna is 47 × 10 mm2 and achieving the measured bandwidth of 18%. The antenna is showing a simple configuration and an effective design method for applying on transparent electronics fields.