Browsing by Author "Lu, Jhe-Ching"

Now showing 1 - 13 of 13

Broadband Planar Magic-T with Marchand Type Power Divider and Balun
(2014)
Chou, Po-Jung
;
Lin, Pei-Chieh
;
Lin, Yun-Wei
;
Lu, Jhe-Ching
;
Chang, Chi-Yang
A new broadband high-order planar magic-T is proposed in this paper. The magic-T is formed by Marchand type power divider and balun. Exact synthesis method based on S-domain highpass prototype using Richard\'s theorem tits the magic-T with the user-defined specifications. By discussing the characteristic impedance of the common element shared by the balun and divider, the magic-T can be designed to match different output impedance. A high-order magic-T with wide bandwidth about 100% and reflection coefficient of -15dB is designed as an example where a combination of microstrip lines, slotlines, double-sided parallel-strip line (DSPSL) and coplanar striplines is applied. The simulation and measurement results are matched well.
Design and Implementation of the Canonical-Form-Like Coupling Scheme with Generalized Chebyshev Responses
(2010-01-01)
Lu, Jhe-Ching
;
Lin, Yun-Wei
;
Chang, Chi-Yang
;
電信工程研究所
;
Institute of Communications Engineering
The canonical-form-like cross-coupling schemes of orders four, six and eight and its implementations are presented for coupled resonator filters. These coupling schemes show similar characteristics to that of the traditional canonical form coupling schemes. The fourth-order filter can be designed to have two pairs of transmission zeros locating on either real or imaginary frequency axes. An example filter designed with one pair of real frequency transmission zeros for selectivity and another pair of imaginary frequency transmission zeros for equalizing the group delay response is introduced. Measured and simulated performances are presented. In addition, the higher order coupling schemes are also discussed.
Design of High-Order Wideband Planar Balun Filter in S-Plane Bandpass Prototype
(2012-07-01)
Lin, Yun-Wei
;
Lu, Jhe-Ching
;
Chang, Chi-Yang
;
電信工程研究所
;
Institute of Communications Engineering
A new high-order wideband planar balun filter is proposed in this paper. The balun filter is exact synthesized based on S-domain bandpass prototype using Richards' Theorem to fit the user-defined specifications. By analyzing the redundant element in the equivalent circuit, the output impedance of the balun filter can be arbitrarily assigned. To use an S-plane bandpass prototype other than a high-pass prototype can shrink the circuit area and improve the stopband performance. The lumped capacitor approximation suppresses the spurious response in the stopband and further reduces the circuit size. A high-order balun filter with a bandwidth of 100% and a reflection coefficient of -15 dB is implemented by combining of microstrip lines, slotlines, and coplanar striplines. The simulation and measurement results match well.
Dual-Band Filters with Frequency-Separated Dual-Path Coupling Scheme
(2010-01-01)
Kuo, Yi-Ting
;
Lu, Jhe-Ching
;
Liao, Ching-Ku
;
Chang, Chi-Yang
;
電信工程研究所
The dual-path topology is provided for dual-band filter design. The frequency-separated property is analyzed, and it shows the capability to design the filtering function separately in each path. Moreover, the dual-path topology is compatible with both symmetric and asymmetric dual-band characteristic. Two microstrip implementations are provided to demonstrate the reliability of dual-path dual-band topology.
Exact Synthesis and Implementation of New High-Order Wideband Marchand Baluns
(2011-01-01)
Lu, Jhe-Ching
;
Lin, Chung-Chieh
;
Chang, Chi-Yang
;
電信工程研究所
;
Institute of Communications Engineering
New ultra-wideband high-order Marchand baluns with one microstrip unbalanced port and two microstrip balanced ports are proposed in this paper. The proposed Marchand baluns are synthesized based on an S-plane high-pass prototype using the Richards' transformation. The responses of the synthesized high-order Marchand baluns are exactly predicted at all real frequencies. All circuit elements are commensurate, which means the electrical lengths of all transmission line elements are a quarter-wavelength long at the center frequency. Two fifth-order Marchand baluns with reflection coefficients of -20.53 and -21.71 dB corresponding to 131% and 152% bandwidth, respectively, are synthesized and realized using the combinations of microstrip lines, slotlines, and coplanar striplines. Simulated and measured results are presented.
Five-Pole Parallel-Coupled Microstrip Cascade Quadruplet Filters for High Selectivity and Flat Group Delay
(2009)
Lu, Jhe-Ching
;
Lin, Yun-Wei
;
Liao, Ching-Ku
;
Chang, Chi-Yang
;
電信工程研究所
The design of five-pole cascade quadruplet microstrip filters is presented. Based on a conventional parallel-coupled structure, good initial physical dimensions can be obtained by the well-known analytical method. Applying source and load to couple to the third resonator two cascaded quadruplets are formed. Two pairs of transmission zeros can be independently located on either real or imaginary frequency axes. Two filters are introduced in this paper that one have two pairs of real frequency transmission zeros for selectivity, and the other have one pair of real frequency transmission zeros for selectivity and another pair of imaginary frequency transmission zeros for group delay equalization. The flat group delay response is particularly sensitive to the unwanted cross coupling. The proposed structure solves this problem and shows a very flat group delay in the passband. The simulated and measured results of the two designed microstrip filters are well-matched.
Generalized Chebyshev Response Parallel-Coupled Filter with Suppression of 2f(0) Spurious Passband
(2008)
Lu, Jhe-Ching
;
Chang, Chi-Yang
;
電信工程研究所
;
Institute of Communications Engineering
High Selectivity and Flat Group Delay ParallelCoupled Microstrip Bandpass Filter with Lumped Element K-Inverters
(2010-01-01)
Lin, Yun-Wei
;
Lu, Jhe-Ching
;
Chang, Chi-Yang
;
Liao, Ching-Ku
;
電信工程研究所
In this paper, high selectivity and flat group delay parallel-coupled microstrip bandpass filter with lump element Kinverter are proposed. By using delay line, cross coupling is introduced and controlled easily to generate finite transmission zeros for selectivity and flat group delay. Finally, 5th-order and 6th-order filters with high selectivity and flat group delay are given as examples.
Microstrip parallel-coupled filters with cascade trisection and quadruplet responses
(2008-09-01)
Lu, Jhe-Ching
;
Liao, Ching-Ku
;
Chang, Chi-Yang
;
電信工程研究所
;
Institute of Communications Engineering
Microstrip parallel-coupled filters with generalized Chebyshev responses are presented. The basic structure of the proposed filter is a conventional parallel-coupled filter of which the physical dimensions can be easily obtained by the well-known analytical method. With the aid of the equivalent circuit corresponding to a conventional parallel-coupled filter, the relative insertion phase from source or load to each open end of resonators can be easily obtained by observing the two-port admittance matrix. Applying the cross coupling from source or load to a proper nonadjacent resonator, a trisection or a quadruplet coupling scheme can be realized with prescribed transmission zeros. More importantly, the proposed trisection can be designed to have a transmission zero on the lower or upper stopband by just adjusting the length of the cross-coupling strip. Using the proposed structure, the conventional time-consuming adjusting procedure to obtain initial physical dimensions of filters is no longer required. In this paper, a fourth-order parallel-coupled filter is used as the basic structure to demonstrate various combinations of transmission zeros. Simulated and measured results are well matched.
New Multiband Coupling Matrix Synthesis Technique and Its Microstrip Implementation
(2010-07-01)
Kuo, Yi-Ting
;
Lu, Jhe-Ching
;
Liao, Ching-Ku
;
Chang, Chi-Yang
;
電機工程學系
In this paper, we present a novel analytical multiband transversal coupling matrix synthesis technique. By properly combining several single-band filtering functions, the multiband filtering function with flexible transmission zeros and various bandwidth are available. The transversal coupling scheme is then transformed into a practically realizable coupling scheme. To verify the feasibility of the proposed method, two dual-band coupling schemes, both single-path and dual-path, are proposed as examples of the dual-band filter design. Finally, the dual-band filter, based on the coupling matrix corresponding to a specific coupling scheme, can be realized using a microstrip parallel-coupled structure.
Quarter-Wave Parallel-Coupled and Interdigital Microstrip Bandpass Filters with Generalized Chebyshev Response
(2010-01-01)
Lin, Yun-Wei
;
Lu, Jhe-Ching
;
Chang, Chi-Yang
;
Liao, Ching-Ku
;
電信工程研究所
Two quarter-wave resonator microstrip bandpass filters with generalized chebyshev response are proposed in this work. By using the delay lines and observing the phase relationship between source and resonators, the phase and amplitude of cross couplings can be easily realized so that a generalized chebyshev response can be implemented. Furthermore, the cross coupling for interdigital structure is proposed. Finally, a 3rd-order high selectivity quarter-wave filter and a 5th-order high selectivity and flat group delay interdigital filter are fabricated to show the feasibility.
Quarter-Wave Stepped-Impedance Resonator Filters with Quadruplet and Canonical Form Responses
(2008)
Lu, Jhe-Ching
;
Chang, Chi-Yang
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, compact microstrip quarter-wave stepped-impedance resonator (SIR) bandpass filters with quadruplet and canonical form responses are proposed. The proposed quadruplet filter can be designed to have a pair of transmission zeros to achieve sharp selectivity. In addition, by applying an extra source-load coupling, two additional transmission zeros on both side of passband are created to further enhance the selectivity. Because the quarter-wave SIRs are adopted, the circuit size of the filters can be largely reduced and the upper stopband can be extended. Two generalized Chebyshev filters corresponding to quadruplet and canonical form coupling schemes are fabricated. Simulated and measured results are matched very well.
Six-Pole Parallel-Coupled Microstrip CQ Filter with Source-Load and Source/Load to Resonator Cross Coupling
(2009)
Lin, Yun-Wei
;
Lu, Jhe-Ching
;
Chang, Chi-Yang
;
Liao, Ching-Ku
;
電信工程研究所
The six-pole cascade quadruplet microstrip filter with source-load and source/load to nonadjacent resonator cross coupling is proposed to achieve generalized Chebyshev responses. The presented coupling scheme achieves similar skirt selectivity as that of a sixth-order fully canonical form filter. In addition, the proposed filter is less sensitive than that of canonical form filter. The initial design can be easily obtained by the design procedure of conventional parallel-coupled filter. With source to the third resonator and load to the fourth resonator cross couplings, two quadruplets are formed. Moreover, a source-load cross coupling forms the third quadruplet. The three quadruplets produce three pairs of finite transmission zeros. By controlling the strength of the cross couplings, the position of the three pairs of zeros can be decided arbitrarily. A design example is provided in this paper. Furthermore, simulation and measurement results are well matched.