Search

In this article, a compact dual-mode λg/2 bandpass filter with the characteristic of harmonic rejection is designed and implemented.The second and third harmonics of the suggested bandpass filter are rejected by using the additional open stubs of the T-type equivalent circuit for the quarter wavelength line. Also, the J-inverter is investigated as functions of the impedance and electrical length of the open stub of dual-mode λg/2 resonator. From the results, the lower impedance of open stub of dual-mode λg/2 resonator is better for the good performance of the dual-mode λg/2 bandpass filter. The harmonic-rejected dual-mode λg/2 bandpass filter shows the characteristic of suppression of harmonics until 8 GHz and the insertion and return losses of 0.96 and 18.89 dB, respectively, at the center frequency of 2.43 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2288–2291, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25457 [ABSTRACT FROM AUTHOR]

A simplified mathematical design method for tapped-line geometry is presented and the stub bandpass filters (BPFs) of λg/4 and λg/2 stubs with a center frequency of 5.8 GHz and a bandwidth of 5% are successfully designed, fabricated, and characterized using this approach. Design parameters for the tapped-line geometry of the filter prototypes are obtained using input (output) admittance toward source (load), where the open-stub and the additional transmission-line with a negative electrical length are taken into account for filter implementation. The electrical lengths of the stubs and lines are functions of the line admittance and J-inverter. The filters are implemented on a RT-duroid substrate and the results from modeling and measurement show good agreement with each other. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2338–2341, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24615 [ABSTRACT FROM AUTHOR]

In this paper, the harmonics suppressed waveguide filter with SIW (substrate-integrated waveguide) structure using inductive windows at satellite communication band is discussed. The SIW structure is realized by via-holes and can be integrated with other circuits on the same substrate. The SIW filter has the insertion loss of 2.85 dB and return loss of 17.57 dB at the center frequency of 12 GHz. Also, the proposed SIW filter has the harmonics suppression under 20 dB until 30 GHz by inserted low-pass filter (LPF). This harmonics suppressed SIW filter can be used in satellite communication systems. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 447–450, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23114 [ABSTRACT FROM AUTHOR]