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In this paper, a novel miniaturized circularly polarized (CP) antenna is proposed for the use in B3 band of Compass Navigation Satellite System (CNSS). The primary radiator is a hexagon patch with four bending strips. A shorting pin is loaded with each strip to miniaturize the dimension of the proposed antenna, which achieves a small electrical size of 0.11λ × 0.11λ × 0.068λ (λ being the wave-length in free space at 1.268 GHz). In order to improve the bandwidth, Y-shaped coupled patches and bending-strips, which act as reactive loading, are coupled to an octagon patch. Four coupled bending-stubs with same turning directions of bending-strips are sequentially placed at the edge of the octagon patch to enhance CP performance. Finally, a prototype of the antenna is implemented and measured. The experimental results reveal that the proposed antenna achieves impedance bandwidth (IBW) of 19.6% (1.175-1.430 GHz) for ∣S11 ∣ ≤ -10 dB and 3-dB axial-ratio bandwidths (ARBW) of 27.5% (1.000-1.320 GHz). The radiation efficiency is more than 75%, and the gain keeps above 1.98 dBic over the B3 band. Thus, the proposed antenna can be a good candidate for the applications of CNSS. [ABSTRACT FROM AUTHOR]

A compact tunable dual-band bandpass filter (BPF) based on substrate integrated waveguide (SIW) and defected ground structure (DGS) is investigated in this paper. The second passband can be flexibly controlled by changing the dimensions of the up- down DGSs whereas the first passband is fixed. The proposed filter exhibits improved selectivity due to the introduction of four left-right DGSs generating transmission zeroes. To verify the design method, a compact dual-band filter with the second center frequency switched among 5.4 GHz, 5.8 GHz, 6.4 GHz and 6.8 GHz and the first center frequency fixed at 4.78 GHz, is designed and fabricated. The simulated and measured results are in good agreement with each other. [ABSTRACT FROM AUTHOR]

A compact quad-band microstrip band-pass filter (BPF) based on novel step-impedance ring resonator (SIRR) is investigated in this paper. The proposed BPF is composed of one ring resonator and input/output coupled structure. The novel resonator is studied and employed to generate four desired independent passbands. A compact quad-band BPF centered at 1.57, 2.45, 3.5 and 5.2 GHz is designed and fabricated. The predicted results are compared with measured data, and good agreement is reported. [ABSTRACT FROM AUTHOR]

A compact tri-band power divider based on triple-mode resonator is proposed in this paper. This tri-mode resonator comprises a conventional half-wavelength resonator, a short stub and an open stub. The interdigital coupled-lines are introduced at the input and the output to improve the performance of this power divider. The proposed tri-band power divider working at 1.57 GHz, 2.45 GHz, 3.50 GHz is simulated and fabricated, and good agreement between the simulated results and the measured results are observed. [ABSTRACT FROM AUTHOR]

A novel planar three-way triple-band power divider is proposed in this article. The circuit is composed of three sections of three transmission lines and planar isolation resistors, which can provide high isolation and good amplitude balance simultaneously at three arbitrary frequencies. The structure of the power divider and the formulas used to determine the design parameters has been given. To verify the validity, a proposed power divider was fabricated and measured at 900, 1800, and 2400 MHz. Both theoretical and simulated results are presented, which are in good agreement with the measured results. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 182–184, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24858 [ABSTRACT FROM AUTHOR]

This article presents a compact branch-line coupler (BLC) for balanced-type circuit application. It was designed by utilizing cascading multisection and capacitance-loading technique for bandwidth increase and size reduction individually. The proposed BLC was simulated and fabricated. Its physical length reduces by 28.7%, while it performs as good as the conventional one. The simulated and the measured results have a good agreement. The method is valid for compact and good performance BLC design. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 198–200, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23992 [ABSTRACT FROM AUTHOR]

A compact ultra-wideband (UWB) bandpass filter (BPF) with a notch band based on a slow-wave half-mode substrate-integrated waveguide (SW-HMSIW) is proposed. The proposed SW-HMSIW is believed to be the first ever reported. Similar to the slow-wave substrate-integrated waveguide (SW-SIW), SW-HMSIWs can achieve highpass characteristics, while the lateral width is reduced by about 50%. To obtain the UWB response, three spiral compact microstrip resonant cells are etched on the SW-HMSIW as a lowpass filter. Moreover, a shortcircuited quarter wavelength L-type resonator is used to achieve a notch band. To validate the design theory, a compact UWB BPF is designed and fabricated. The simulated results are compared with the measured results, and good agreement is reported. [ABSTRACT FROM AUTHOR]

A novel and compact tri-band microstrip-fed monopole antenna with dual-polarisation characteristics for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications is proposed. The antenna is composed of a partial ground and a Y-shaped radiating patch that consists of two unequal monopole arms and a modified circle monopole. The antenna is able to generate three separate impedance bandwidths to cover the frequency bands of the WLAN (2.4-2.484 and 5.8 GHz) and the WiMAX (3.4-3.7 GHz). In addition, the antenna is circularly polarised in both the WLAN bands. Furthermore, the antenna structure is extremely simple, durable and occupies small space, making it suitable for practical applications. [ABSTRACT FROM AUTHOR]