Abstract-A novel dual-band bandpass filter with meander-loop resonator and complement split-ring resonator (CSRR) defected ground structure (DGS) is proposed in this letter. Microstrip meanderloop resonator and CSRR DGS are operated for respective passbands. Several finite attenuation poles in stopbands are realized to improve the selectivity of the proposed bandpass filter and isolation between the two passbands. Compact size, dual band and high selectivity characteristics are realized by this type of filter structure. The filter is evaluated by experiment and simulation with very good agreement.

Abstract-A compact dual-band bandpass filter using equal-length split-ring resonators (SRRs) is proposed in this paper. The tworesonance frequency response of equal-length split-ring resonator is described in detail. A cross-coupled dual-band filter with four equallength split-ring resonators is designed. Several finite out-of-band attenuation poles are realized to improve the selectivity of the proposed filter. The measurement of the filter is in good agreement with the simulation.

A novel multiband and vertically/horizontally polarized omnidirectional antenna is proposed for 2G/3G/LTE mobile communication systems. The proposed antenna is a combination of a modified asymmetric biconical for vertical polarization (VP) and six printed dipoles with concentric placement for horizontal polarization (HP). The VP element consists of two modified cones with different diameters, designed to work in the multiband . Printed dipoles of the HP element are fed by a six-way power splitter printed on the substrate. The HP element is nested between two cones of the VP element, forming a compact structure. The bottom cone can be used as the reflector for VP and HP in the overlapping work frequencies band for 3G and LTE communication systems. The VP element achieves a bandwidth of 17.4% and gain of 1.5 dBi in the 806 960-MHz band. The HP element achieves a bandwidth of 35% (1880 2700 MHz) directly overlapping with the VP-element higher frequency band. An isolation of 25 dB is achieved in the overlapping band. The cross-polarization levels in the azimuth plane for both VP and HP are lower than 15 dB. Index Terms-Asymmetric biconical, broadband antenna, dualpolarized antenna, omnidirectional antenna, printed dipole.

Abstract-A novel dual-mode dual-band bandpass filter based on conventional triangular dual-mode filter is designed in this paper. The filter has the characteristics of compact structure, low insertion loss and so on. Based on the current design schemes, the design of dualmode and dual-band filter can be integrated in a novel filter structure. Several attenuation poles in the stopband are realized to improve the selectivity of the proposed bandpass filter. The experimented results were in good agreement with simulated results.

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