Quan Xue

Dual-Band Bandpass Filters Using Stub-Loaded Resonators

Dual-band bandpass filters using novel stub-loaded resonators (SLRs) are presented in this letter. Characterized by both theoretical analysis and full-wave simulation, the proposed SLR is found to have the advantage that the even-mode resonant frequencies can be flexibly controlled whereas the odd-mode resonant frequencies are fixed. Based on the proposed SLR, a dual-band filter is implemented with three transmission zeros. To further improve the selectivity, a filter with four transmission zeros on either side of both passbands is designed by introducing spur-line. The measured results validate the proposed design.

Novel 1-D microstrip PBG cells

Novel one-dimensional (1-D) microstrip photonic bandgap (PBG) cells are proposed. They are sections of microstrip line with special perforation patterns etched on the line itself. As examples, two types of PBG cell are investigated. Simulation and experiments show that the cell exhibits remarkable slow-wave and band-stop effects. An equivalent L-C circuit is used to model the PBG cell. Several cells connected in series form an excellent band-stop filter.

Dual-Mode Dual-Band Bandpass Filter Using Stacked-Loop Structure

In this letter, a dual-mode dual-band bandpass filter using stacked-loop structure is proposed, which allows two transmission paths to radio frequency (RF) signals. Each of them using dual-mode resonators results in respective passband. This can provide convenience to easily change one passband frequency, while another keeps almost the same. Several attenuation poles in the stopband are realized to improve the selectivity of the proposed bandpass filter. The theoretical and measured results are presented and show good agreement

A Band-Notched Ultrawideband Printed Monopole Antenna

In this letter, a band-notched ultrawideband (UWB) antenna is presented and the notched-band characteristic is realized by a compact coplanar waveguide (CPW) resonant cell (CCRC). The antenna with a total size of 46 mm

An Analytical Approach for a Novel Coupled-Line Dual-Band Wilkinson Power Divider

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Novel Dual-Mode Dual-Band Filters Using Coplanar-Waveguide-Fed Ring Resonators

30 mm operates in a band from 2.67 to over 12 GHz, and shows omnidirectional radiation patterns. Measurements indicate that the antenna presents a notched band from 5.10 to 5.94 GHz for

Novel Ultra-Wideband (UWB) Multilayer Slotline Power Divider With Bandpass Response

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Novel Centrally Loaded Resonators and Their Applications to Bandpass Filters

, which covers the wireless local area network (WLAN) band. The time-domain behaviors and the CCRC are discussed and the group delay is given experimentally. Also, parametric studies are performed numerically in the end.

Balanced Bandpass Filters Using Center-Loaded Half-Wavelength Resonators

A novel generalized coupled-line circuit structure for a dual-band Wilkinson power divider is proposed. The proposed power divider is composed of two coupled lines with different even- and odd-mode characteristic impedances and two lumped resistors. Using rigorous even- and odd-mode analysis, the analytical design equations for this proposed power divider are obtained and the ideal closed-form scattering parameters are constructed. Since the traditional transmission line is a special case of coupled line (coupled coefficient is zero), it is found that traditional noncoupled-line dual-band (including single band) Wilkinson power dividers and previous dual-band coupled-line power dividers are special cases of this generalized power divider. As a typical example, which could only be designed by using this given design equations, a compact microstrip 3-dB power divider operating at both 1.1 and 2.2 GHz is designed, fabricated, and measured. There is good agreement between calculated and measured results.

Design and Analysis of a Low-Profile and Broadband Microstrip Monopolar Patch Antenna

This paper presents a novel approach for designing dual-mode dual-band bandpass filters with independently controlled center frequencies and bandwidths. Two microstrip perturbed ring resonators are employed to obtain dual-mode dual-band responses. Novel feeding structures are introduced to simultaneously feed the ring resonators and conveniently control the coupling strength between resonators and feeding lines, resulting in a wide tunable range of external quality factors. Two kinds of filter configurations with compact size are proposed. Both of them provide sufficient degrees of freedom to satisfy various requirements of external qualify factors and coupling coefficients at both passbands. Therefore, the center frequencies and fractional bandwidths of both passbands can be independently tuned to desired specifications within a wide range. To verify the proposed method, four filters are implemented. The measured results exhibit dual-mode dual-band bandpass responses with high selectivity.