Browsing by Author "Jiang, MS"

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Design of parallel-coupled microstrip filters with suppression of spurious resonances using substrate suspension
(2004-01-01)
Kuo, JT
;
Jiang, MS
;
Chang, HJ
;
電信工程研究所
;
Institute of Communications Engineering
Substrate suspension is used to suppress the spurious response of microstrip bandpass filters at twice the passband frequency (2f(o)). It is known that a proper height of substrate suspension can be used to equalize the even- and odd-mode phase velocities for coupled microstrip lines. In this paper, this property is applied to design the coupled stages of a parallel-coupled line filter so that the spurious response at 2f(o) can be completely suppressed. The individual image impedance for each coupled stage is changed accordingly. Required filter design formulas are derived for a series of coupled stages having different image impedances. Several filters made on a substrate of relative high dielectric constant are designed and fabricated. The measured results show that a rejection level of better than -40 dB to the spurious resonance at 2f(o) can be obtained.
Enhanced microstrip filter design with a uniform dielectric overlay for suppressing the second harmonic response
(2004-09-01)
Kuo, JT
;
Jiang, MS
;
電信工程研究所
;
Institute of Communications Engineering
Parallel-coupled microstrip filters are designed to suppress spurious response at twice the passband frequency (2f(o)) with a uniform dielectric overlay. The overlay dielectric is used to equalize the modal phase velocities of each coupled stage. Based on the method, we have a large degree of freedom in choosing thickness and permittivity or the overlay dielectric. The image impedances of all the coupled stages in such a filter need adjusting to complete the filter synthesis. Two filters are fabricated and measured results show a good agreement with the simulation. A suppression of at least 40 dB to the spurious responses at 2f(o) is achieved.
Parallel-coupled microstrip filters with over-coupled stages for multispurious suppression
(2005)
Jiang, MS
;
Wu, MH
;
Kuo, JT
;
電信工程研究所
;
Institute of Communications Engineering
An inherent zero of a microstrip coupled stage near twice the design frequency (2f(o)) is found tunable by varying its coupling length. This zero is used to suppress the unwanted response of parallel-coupled line filters at this frequency by using over-coupled end stages. The above idea is extended to design over-coupled middle stages for suppressing the spurious vertical bar S-21 vertical bar peaks at 3f(o) and 4f(o) of the filter, so that the upper stopband can be greatly enhanced up to 5f(o). The passband preserves a response as good as the traditional design. Measured results have a good agreement with simulation data and show that the idea works very well.
Study of parallel coupled-line microstrip filter in broadband
(2006-02-01)
Chen, CC
;
Kuo, JT
;
Jiang, MS
;
Chin, A
;
傳播研究所
A parallel coupled-line microstrip filter is designed and implemented on PCB with its maximum bandwidth. In this paper, this filter has presented almost very good characteristics including the simulated bandwidth of 67%. the measured bandwidth of 64%, lower insertion loss of 1.27 dB. and flat response in the pass-band. The maximum bandwidth fabricated on PCB shows good agreement with the theoretically calculated bandwidth of 70% due to the narrower gap size between the coupled lines. (C) 2005 Wiley Periodicals, Inc.