• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.5
• /
• pp.598-605
• /
• 2012

In this paper, a multi-layer dual-band bandpass filter using aperture-coupling is proposed. Two coupling paths are formed with the two apertures which exist between two dual-mode resonators. The coupling coefficients can be adjusted without changing the shape of resonators. The bandwidth of the second passband can be adjusted without affecting the bandwidth of the first passband using the size of an aperture between stubs of the dual-mode resonator. The aperture coupling mechanism is theoretically analysed. The dual-mode bandpass filter for the 2.4 GHz WLAN, 3.5 GHz WiMax was designed and fabricated. The fabricated filter shows centered 2.45 GHz and 3.5 GHz with 9 % and 8 % of the bandwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.2
• /
• pp.124-128
• /
• 2009

This raper proposes a dual-bandstop filter, which is based on a metamaterial transmission line using the composite right/left-handed (CRLH) and dual composite right/left-handed (D-CRLH) structures. The metamaterial structure is used for miniaturization and dual-bandstop operation at the TDMB frequency range (195 MHz) and DVB-T/H frequency range (670 MHz). The size of the proposed filter is $30{\times}15\;mm$, and the -10 dB bandstop fractional bandwidth is approximately 73 % and 50 % at each frequency, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.9
• /
• pp.852-857
• /
• 2011

In this paper, the application of a variable characteristic impedance transmission line that can be used to design a dual-band bandpass filter(BPF) is presented. The proposed filter offers a fixed first frequency passband and a controllable second passband. The tuning of the second passband is achieved by varying the characteristic impedance of and open shunt stub line in a stub loaded resonator(SLR) with the help of a defected ground structure(DGS) transmission line and varactor diodes. In order to validate the proposed structure, a two stage dual-band BPF with three transmission zeros was implemeted and experimentally verified based on its theoretical predictions and simulations.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.2
• /
• pp.463-469
• /
• 2016

In this paper, the use of a dual composite right/left-handed coplanar waveguide (CPW) transmission line is proposed for the design of a band rejection filter. The notch property of the filter is achieved by combining the convex signal line with the shorted concave meander line, and the equivalent circuit model is extracted from the geometry of the unit cell for organizing the band rejection property. Then the equivalent parameters of the unit cell are analyzed to identify those behaviors. And the dispersion characteristics and energy distributions are simulated. In the end, the band rejection filter is manufactured by cascading two proposed unit cells. We show that the measurement result for the resonant frequency demonstrates good agreement with the simulation result and the band rejection filter provides a rejection performance of 17.5 dB at the stopband frequency ranging from 869 MHz to 894 MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.3
• /
• pp.278-283
• /
• 2004

Due to the complex arrangement of frequency plans and spatial overages in modern satellite communications, channels that are non-contiguous in frequency may be amplified by a single power amplifier and transmitted to the ground through one beam. In this paper, a dual-mode canonical filter with dual-passband is presented. The filter adopts dual-mode technique for mass and volume reduction. Canonical structure is adopted for maximum transmission zero realization. To validate the design technique, a 6-pole dual-mode canonical dual-passband filter for Ka-band(30/20 ㎓) satellite transponder is realized. The measured frequency response of the filter shows good agreement with the computed one.

• Journal of Advanced Navigation Technology
• /
• v.27 no.1
• /
• pp.57-62
• /
• 2023

This paper proposes a tri-band bandpass filter using dual-mode stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with open stubs and parallel coupled lines (PCLs) that have inter-digital and comb-line shorted ends. Two U-shaped SIRs with open stubs build the first and third passband, and the central PCL resonators build the second passband. Five resonators and coupling structures are theoretically analyzed to derive the scattering parameters of the proposed filter. A novel tri-band bandpass filter is designed and fabricated using the induced scattering parameters. The measured result of the fabricated tri-band bandpass filter shows a good agreement with the simulated one.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.2
• /
• pp.505-513
• /
• 1996

In this paper the dual-mode bandpass filters with a Chebyshev response are designed and manufactured at Ku-band as well as K-band. Manufactured filters are resonated by two independent orthogonal $TE_{113}$ circular-cavity modes and characterized by 4-pole Chebyshev function. One is operating at a center frequency of 12.5GHz with a bandwidth of 100MHz and the other, a center frequency of 19.25GHz with 120MHz, respectively. The measureed experimental results of a 12.5GHZ dual-mode filter ahve a 1.2dB intertion loss in the passband and 65dB out-of-rejection, and a 19.25GHz filter has a 1.55dB insertion loss and 70dB out-of-rejection. These experimantal results shoults show good agreements with the design specifications.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.8
• /
• pp.1653-1658
• /
• 2011

A novel circuit structure of dual-band bandstop filters is proposed in this paper. This structure comprises two shunt-connected tri-section stepped impedance resonators with a transmission line in between. Theoretical analysis from the equivalent circuit and design procedures are described. We represented graphs for filter design from the derived synthesis equations by resonance condition of circuits. Notably, advantages of the proposed filter structure are compact size in design, wide range of realizable resonance frequency ratio, and more realizable impedances.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.4 no.2
• /
• pp.119-125
• /
• 2011

A novel circuit structure of dual-band bandstop filters is proposed in this paper. This structure comprises two shunt-connected tri-section stepped impedance resonators with a transmission line in between. Theoretical analysis from the equivalent circuit and design procedures are described. We represented graphs for filter design from the derived synthesis equations by resonance condition of circuits. Notably, advantages of the proposed filter structure are compact size in design, wide range of realizable resonance frequency ratio, and more realizable impedances.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.4
• /
• pp.1048-1058
• /
• 1996

In this paper, a small duplexer is designed and implemented using a H-plane T-junction and Transmitting/Geceiving filte with a dual mode cavity resonator for Ku-band. Transmitting(TX) filter is designed at center frequeny 12.5 GHz and Receiving(RX) filter, at center frequency 14.5 GHz. Both filters have a 100 MHz bandwidth. This duplexer is reduced to about 40% by the conventional duplexer of cavity bandpass filter structure in size. Operating characteristics of duplexer is optimized in order not to distors matching characteristics of each filter when interfaced to a H-plane T-junction. Consequently, the responses of filter with H-plane T-junction nearly coincide with that of filter itself.