Browsing by Author "Kuo, JT"

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A compact distributed low-pass filter with wide stopband
(2001)
Kuo, JT
;
Shen, J
;
電信工程研究所
;
Institute of Communications Engineering
A distributed parallel resonance circuit is used to design a very compact low-pass filter with cutoff frequency 0.5GHz. The circuit has a section of transmission line shunt with an interdigital capacitor connecting with two low-impedance lines at both of its terminals. A finite transmission zero can be generated near the passband edge so that the filter has a sharp transition response. In addition, the stopband can be extended to more than 6GHz by properly choosing the structural parameters of the circuit. The measured responses match with the simulation quite well.
A fully planar microstrip coupled-line coupler with a high coupling level
(2005-07-20)
Chen, CC
;
Kuo, JT
;
Jiang, M
;
Chin, A
;
傳播研究所
A fully planar microstrip coupler with a high coupling level tip to 4 dB is fabricated on PCB. Based on the conventional coupled-line structure, a gap Size of coupled lines about 14 mu m is realized by low cost IC process. It has a single stage and requires no bond wire. In measurement, a bandwidth more than 50% and isolation and return loss better than -20 dB are achieved. The measured responses have good agreement with EM simulation data. (c) 2005 Wiley Periodicals, Inc.
A microstrip elliptic function filter with compact miniaturized hairpin resonators
(2000-03-01)
Kuo, JT
;
Maa, MJ
;
Lu, PH
;
電信工程研究所
;
Institute of Communications Engineering
A four-pole elliptic function bandpass filter is designed using compact miniaturized microstrip hairpin resonators. It is shown that the filter occupies a very small area. The full-wave simulator IE3D is used to design the resonator and to calculate the coupling coefficients of the three basic coupling structures. Measurement results are compared with the computed responses.
A new compact microstrip stacked-SIR bandpass filter with transmission zeros
(2003)
Shih, E
;
Kuo, JT
;
電信工程研究所
;
Institute of Communications Engineering
This paper presents a new class of bandpass filters based on a stacked-SIR (stepped impedance resonators) configuration. By stacking multi-coupled SIR's, the longitudinal dimension of the resulting filter is not increased despite the increase of the filter order, so that the area of the whole filter is very compact. The use of SIR's assures that the filters have a wide upper stopband. In addition, with proper tapped input and output couplings, this new bandpass filter structure is capable of generating at least two transmission zeros. Of filters of orders 2 and 4, simulated responses show three transmission zeros in the stopband. Two third-order filters with transmission zeros purposely located at twice the center passband frequency (2f(0)) are fabricated and measured to demonstrate the design.
An efficient analysis of shielded single and multiple coupled microstrip lines with the nonuniform fast Fourier transform (NUFFT) technique
(2004-01-01)
Su, KY
;
Kuo, JT
;
電信工程研究所
;
Institute of Communications Engineering
A nonuniform fast Fourier transform (NUFFT) technique is incorporated into the spectral-domain approach for the analysis of shielded single and multiple coupled microstrio lines. Each of the spectral-domain Green's functions is decomposed into an asymptotic part and a remaining part. At the interface of layered dielectrics with conducting strips, the product of a basis function and an associated Green's function constitutes an expansion E-field. The inverse Fourier transform (IFT) of the expansion E-field is its spatial distribution all over the interface. We take this advantage to match the final boundary conditions on all the conducting strips simultaneously. As a result, if all the strips are at one interface, the number of operations required in this method is proportional to N-l, but not to N-l(2), where N-l is the number of the strips. The IFT of the asymptotic part of each expansion E-field can be obtained analytically, and that of the remaining part can be quickly processed by the NUFFT. The Gauss-Chebyshev quadrature is used to accelerate the computations of the integrals resulted from the Galerkin's procedure. The proposed method is also applied to investigate the dispersion characteristics of coupled lines with finite metallization thickness and of coupled lines at different levels. A,convergence analysis of the results is presented and a comparison of used CPU time is discussed.
Analytical calculation for DC inductances of rectangular spiral inductors with finite metal thickness in the PEEC formulation
(2006-02-01)
Kuo, JT
;
Su, KY
;
Liu, TY
;
Chen, HH
;
Chung, SJ
Inductances of rectangular spiral inductors with finite metal thickness are evaluated by the partial element equivalent circuit (PEEC) technique. The six fold partial self and mutual inductance integrals resulting from the PEEC partitions are found to have analytical expressions, so that the singularities of the integrands can be overcome and the theoretical or "exact" results can be obtained very efficiently. Via and underpath required for input/output connection can also be included in the calculation. Calculated inductance values for 20 square spiral inductors are checked against measured data published in open literature. Dependence of inductance values on metal thickness is investigated for two specific spiral structures.
Analytical evaluation of MoM matrix elements for the capacitance of microstrip discontinuities
(2001)
Su, KY
;
Kuo, JT
;
資訊工程學系
;
Department of Computer Science
An analytical integration formula is derived for the four-fold integral involved in analyzing microstrip discontinuities by the Galerkin's method of moments (MoM). The conductors can be discretized into rectangular subsections with arbitrary dimensions. Application of this newly derived formula to the analysis of some microstrip discontinuities shows that the calculated results have a good convergent behavior. Some results for microstrip open-ends and series gaps are presented.
Analytical evaluation of the MoM matrix elements for the capacitance of a charged plate
(2002-05-01)
Kuo, JT
;
Su, KY
;
電信工程研究所
;
Institute of Communications Engineering
Closed-form expression is derived for the fourfold integral involved in the evaluation of the capacitance of a charged plate using the Galerkin's procedure in the method of moments. The dimensions of each rectangular subsection for discretizing the conducting plate can be arbitrary. The calculated solutions converge faster than the point-matching results, as expected.
Application of two-dimensional nonuniform fast Fourier transform (2-D NUFFT) technique to analysis of shielded microstrip circuits
(2005-03-01)
Su, KY
;
Kuo, JT
;
電信工程研究所
;
Institute of Communications Engineering
A two-dimensional nonuniform fast Fourier transform (2-D NUFFT) technique is developed for analysis of microstrip circuits in a rectangular enclosure. The 2-D Fourier transform of a nongrid point is approximated by Fourier bases in a square neighborhood with (q + 1) by (q + 1) grid points. The square neighborhood can be reduced to an octagonal region with q(2)/2 + 3q + 1 grid points without sacrificing accuracy if q is sufficiently large. This technique allows an arbitrary discretization scheme on conductors and shows a great flexibility for the analysis. Asymmetric rooftop functions are inevitably used to expand surface current densities on conductors. Based on the spectral-domain approach, all elements of the final method-of-moments matrix are double summations of products of a weighted Green's function and trigonometric functions. By using the proposed technique, the double summations at all sampled points can be obtained via the 2-D NUFFT. The scattering parameters of a compact miniaturized hairpin resonator, an interdigital capacitor, and a wide-band filter are calculated. The-calculated results show good agreement with measurements.
Design of bandpass filters with parallel three-line coupled microstrips
(2001)
Kuo, JT
;
Shih, E
;
Lee, WC
;
電信工程研究所
;
Institute of Communications Engineering
Bandpass filters are designed based on parallel coupled three-line microstrip structures. The relation between the circuit parameters of a three-line coupled microstrip section and an admittance inverter is established. A design graph for substrate with epsilon(r) = 2.2 is provided. Two Chebyshev filters, of order 2 and 1dB passband ripple, with fractional bandwidths 40% and 60% are fabricated and measured. Good agreement between prediction and measurement is obtained.
Design of microstrip bandpass filters with a dual-passband response
(2005-04-01)
Kuo, JT
;
Yeh, TH
;
Yeh, CC
;
電信工程研究所
;
Institute of Communications Engineering
This paper presents a rigorous design of microstrip bandpass filters with a dual-passband response in parallel-coupled and vertical-stacked configurations. Based on resonance characteristics of a stepped impedance resonator (SIR), the second resonant frequency can be tuned over a wide range by adjusting its structure parameters. Emphasis is placed on filter synthesis for simultaneously matching in-band response and singly loaded Q by using tapped input/output couplings for the two designated passbands. Fractional bandwidth design graphs are used to determine proper geometric parameters of each coupled stage when filter specification is given. Realizable fractional bandwidths of the two passbands for a coupled SIR structure are clearly depicted in fractional bandwidth design graphs. Several experimental litters are fabricated and measured to demonstrate the design.
Design of microstrip bandpass filters with aperture coupled miniaturized hairpin resonators
(2001)
Kuo, JT
;
Jou, CF
;
Chen, CC
;
資訊工程學系
;
Department of Computer Science
A four-pole elliptic function microstrip filter at 2.4 GHz with fractional bandwidth of 4% is realized using compact miniaturized resonators. The configuration of this filter consists of two back-to-back arrays of resonators on two dielectric layers. The common ground plane is located between the two layers. The signal in the upper dielectric surface can be coupled to the opposite side of the surface through the aperture on the common ground plane. The measured results show a good agreement with the simulation.
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.
Design of quasi-elliptic function filters with a dual-passband response
(2004-10-01)
Kuo, JT
;
Cheng, HS
;
電信工程研究所
;
Institute of Communications Engineering
Compact miniaturized hairpin resonators are used to design cross-coupled filters with a dual-passband response of elliptic function type. The hairpin resonators are treated as a stepped impedance resonator (SIR) in analysis. In a filter, two different hairpin resonators are used to establish proper couplings required for the two design frequencies. Two filters are fabricated and measured. The results show a good agreement with the simulation.
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.
Evaluation of spatial Green's functions for microstrips: fast Hankel transform algorithm and complex image method
(1998-05-28)
Hsieh, RC
;
Kuo, JT
;
電信工程研究所
;
Institute of Communications Engineering
The fast Hankel transform (FI-IT) algorithm and complex image method (CIM) are employed to evaluate the spatial-domain Green's function for a multilayered microstrip structure. The results are compared with those obtained by exact numerical integration. It is found that both techniques have high efficiency and the FHT has better accuracy than the CIM.
Fast full-wave analysis of planar microstrip circuit elements in stratified media
(1998-09-01)
Hsieh, RC
;
Kuo, JT
;
電信工程研究所
;
Institute of Communications Engineering
The fast Hankel transform (FHT) algorithm is implemented in the mixed-potential integral-equation (MPIE) analysis of planar microstrip circuits in stratified media. The spatial-domain Green's functions are accurately and quickly obtained by applying the FHT algorithm to the exact spectral-domain counterparts, Therefore, the entire analysis procedure has high accuracy and efficiency, A nonuniform partition scheme is used to effectively model the rapid change of current distributions around discontinuities. A generalized supplementary equation accounting for arbitrary termination conditions at both feeding and load ends is also derived. The proposed method is used to design a single-stub band-stop filter and a compensated de block circuit. Experimental measurements are performed to validate the computation.
Fast full-wave characterization of arbitrary planar microstrip geometries
(1997)
Hsieh, RC
;
Kuo, JT
;
電信工程研究所
;
Institute of Communications Engineering
A very fast computation method is proposed for the mixed potential integral equation (MPIE) analysis of microstrip elements in a multilayered medium. The fast Hankel transform (FHT) algorithm is employed in this method to calculate the spatial-domain Green's function. Calculated results for some microstrip filters are compared with measurements.
Growth rate regulation of lac operon expression in Escherichia coli is cyclic AMP dependent
(2003-10-23)
Kuo, JT
;
Chang, YJ
;
Tseng, CP
;
生物科技學系
;
Department of Biological Science and Technology
In contrast to the ribosomal RNA gene expression increasing with growth rate, transcription of the lac operon is downregulated by cell growth rate. In continuous culture, growth rate regulation of lac promoter was independent of carbon substrate used and its location on the chromosome. Since the lac operon is activated by cyclic adenosine monophosphate (cAMP), which decreases with increasing cell growth rate, expression of plac-lacZ reporter fusion was analyzed in cya mutant under various growth conditions. The results demonstrated that expression of plac-lacZ in cya mutant was both lower and growth rate independent. In addition, ppGpp (guanosine tetraphosphate) was not involved in the mechanism of growth rate regulation of the lac promoter. Thus, the results of this study indicate that cAMP mediates the growth rate-dependent regulation of lac operon expression in Escherichia coli. (C) 2003 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.
Hybrid-mode computation of propagation and attenuation characteristics of parallel coupled microstrips with finite metallization thickness
(1997-02-01)
Kuo, JT
;
Itoh, T
;
電信工程研究所
;
Institute of Communications Engineering
The hybrid-mode mixed spectral domain approach (MSDA) is formulated to investigate the dispersion nature of multiple coupled microstrip lines with arbitrary metallization thickness, Incorporated into the solution procedure, a new set of basis functions with delta(-1/3) field singularity near conductor edges is found to be effective in calculating both the phase and attenuation constants, The computation of conductor loss is based on the perturbation procedure, Over a broad band of frequency spectrum, excellent agreement is obtained between the calculated results and existing experiment data for the metallic losses of a single microstrip and effective dielectric constants of coupled lines, The influence of finite metallization thickness on the frequency dependent modal propagation and attenuation characteristics is presented for both a three-line and four-line structure.