Design of Triple-Passband Microwave Filters Using Frequency Transformations

Lee, Juseop; Sarabandi, Kamal

doi:10.1109/tmtt.2007.912206

Cited by 65 publications

(50 citation statements)

References 10 publications

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“…커플링 매트릭스를 이용하여 다중 대역을 형성 하는 방법도 있으나, 대부분 cavity나 waveguide 구조 로 구현된다 [5]～ [7] . 평면형 설계를 위해 교차 결합 구 조를 이용한 연구도 진행되어 왔지만, 이 경우는 공 진기 설계, 공진 기간 구조에 따른 커플링 계수 추출 등의 설계 시간이 길어지고 공진기들 간의 한정된 Q factor로 인해 높은 삽입 손실을 야기하며, 다수의 공 진기를 평면상에 배치하는 과정에서 구조적으로 소 형화가 어렵기 때문에 필터의 전체 크기도 커지게 된다 [8], [9] .…”

Section: ⅰ 서 론unclassified

A Filter Synthesis Method for Multi-Band Filter Design

Lee¹,

Lee²,

Lim³

2010

The Journal of Korean Institute of Electromagnetic Engineering

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In this paper, we presented a new LC prototype synthesis method for the multi-band filter. For synthesis a multi-band filter with the required frequency response, we proposed the diagram of poles and zeros, also, we proposed the optimization process for finding the combination of optimized poles and zeros. From the transfer and reflection functions calculated from poles and zeros, we performed the quasi-elliptic LC prototype synthesis of multi-band filter. Using the proposed LC prototype synthesis method of multi-band filter, dual-band filter operating at GSM(880～960 MHz) and ISM(2,400～2,500 MHz) and triple-band filter operating at GSM(880～960 MHz) and ISM(2,400～2,500, 5,725～5,850 MHz) were designed and fabricated.

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Section: ⅰ 서 론unclassified

A Filter Synthesis Method for Multi-Band Filter Design

Lee¹,

Lee²,

Lim³

2010

The Journal of Korean Institute of Electromagnetic Engineering

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“…Multiband antennas [1,2] and filters [3][4][5][6][7][8][9] have been investigated with new synthesis methods or innovative designs. In [3], the multiband bandpass filter is realized by either placing transmission zeros within the passband of a wideband filter or employing higher order resonances.…”

Section: Introductionmentioning

confidence: 99%

Planar Multiband Bandpass Filter With Multimode Stepped-Impedance Resonators

Chiou¹,

Kuo

2011

PIER

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Abstract-Planar multiband bandpass filters are implemented based on the versatile multimode stepped-impedance resonators (SIRs). The resonant spectrum of a SIR can be calculated as functions of the length ratios for various impedance ratios of the high-and low-impedance sections. Thus, by properly selecting the geometric parameters and designing the input/output coupling structure, the SIRs are feasible to realize multiband multimode filters. Using a single SIR, a dualmode dual-band, a dual-mode triple-band or a hybrid dual-/triplemode dual-band bandpass filter can be realized. Emphasis is also placed on designing specified ratios of center frequencies and fractional bandwidths of the passbands. To extend the design flexibility, extra shunt open stubs are used to adjust the ratio of the passband frequencies. In addition, sharpness of the transition bands is improved by designing the input/output stages. Simulation results are validated by the measured responses of experimental circuits.

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“…They have been widely used in microwave filters due to their small size, planner structure and narrow realizable bandwidth. Although these resonators or other modified versions of them such as hexagonal [2][3][4] and spiral resonators [5,6] have been used to realize canonical [7][8][9][10][11][12][13], dual [14][15][16][17][18][19][20][21], triple [22,23] and quadpassband filters [24] with complicated transmission characteristics, all of these filters suffer from the time consuming full-wave-based process of determining the physical parameters of the filter from the desired coupling factor and Q ext . The ability of soft computing techniques in modeling complicated problems in a vanishingly short time instead of using numerical or analytical approach [25][26][27][28][29][30][31][32] may provide a fast and accurate solution to this problem.…”

Section: Introductionmentioning

confidence: 99%

Active Learning Method for the Determination of Coupling Factor and External Q in Microstrip Filter Design

Rezaee¹,

Tayarani²,

Knöchel³

2011

PIER

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Abstract-In the final step of any filter design process, the desired center frequency, coupling factor and external quality factor (Q ext ) are used to determine the physical parameters of the filter. Although in the most cases the physical dimensions of a single resonator for a given center frequency are determined using exact analytical or simple approximate equations, usually such simple equations cannot be found to easily relate the required coupling factor and Q ext to the physical parameters of the filter. Analytical calculation of coupling factor and Q ext versus dimensions are usually complicated due to the geometrical complexities or in some cases such as microstrip resonators due to the lack of exact solution for the field distribution. Therefore coupling factor and Q ext of various kinds of resonators, especially microstrip resonators, are related to the physical parameters of the structure by the use of time consuming full wave simulations. In this paper a surprisingly fast and completely general approach based on a soft computing pattern-based processing technique, called active learning method (ALM) is proposed to overcome the time consuming process of coupling factor and Q ext determination. At first the ALM technique and the steps of modeling are generally described, then as an example and in order to show the ability of the method this modeling approach is implemented to model the coupling factor and Q ext surfaces of microstrip open-loop resonators versus physical parameters of the structure. Using the ALM-based extracted surfaces for coupling factor and Q ext , two four pole Chebychev bandpass filters are designed and fabricated. Good agreement between the measured and simulated results validates the accuracy of the proposed approach.

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Design of Triple-Passband Microwave Filters Using Frequency Transformations

Cited by 65 publications

References 10 publications

A Filter Synthesis Method for Multi-Band Filter Design

A Filter Synthesis Method for Multi-Band Filter Design

Planar Multiband Bandpass Filter With Multimode Stepped-Impedance Resonators

Active Learning Method for the Determination of Coupling Factor and External Q in Microstrip Filter Design

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