Wideband Bandstop Filter Based on Capacitively Coupled λ/4 Short-Circuited Lines

Thai Hoa Duong,Ihn Seok Kim 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.3

A new wideband bandstop filter(BSF) with a sharp roll-off characteristic is introduced in a stripline structure in this paper. The BSF consists of two sections: the first is two capacitively coupled λ/4 short-circuited lines with opposite ground positions, while the second is a capacitively coupled λ/4 short-circuited line. The BSF provides three transmission zeros within the stopband and better than 22 ㏈ rejection over the whole wireless local area network (WLAN) band from 5.15 to 5.825 ㎓. The BSF, cascaded to an U.S. ultra-wideband(UWB: 3.1~10.6 ㎓) bandpass filter(BPF), is simulated with HFSS and realized with low-temperature co-fired ceramic(LTCC) green tape with a dielectric constant of 7.8. The measurement results agree well with the HFSS simulation results. The size of the UWB BPF including the BSF is 3×6.3×0.45 ㎣.

Miniaturized Capacitively Loaded Step-Impedance Bandpass Filter in Multilayer Substrate

Thai Hoa, Duong,Dinh Chien, Hoang,Kim, Ihn Seok 慶熙大學校 레이저 工學硏究所 2007 레이저공학 Vol.18 No.-

In this paper, a miniaturized low insertion loss interdigital bandpass filter with capacitively loaded stepped impedance resonators (SIR) in Low Temperature Co-fired Ceramic (LTCC) technology is introduced. By using SIR and capacitive loading structures based on 6_(r) = 41.77 substrates, a wideband interdigital bandpass filter has been realized for the frequency range from 3.1 GHz to 4.8 GHz. Measurement shows insertion loss less than 0.8 dB, return loss better than 15 dB in the pass band with the center frequency at 3.95 GIIz and bandwidth ratio of 43 %. The filter has a size of 2.15 × 2.6 × 0.85㎣.

New UWB 1:2 Power Divider with Flat In-Band Splitting and Bandpass Filtering Functions

Thai Hoa Duong,Ihn Seok Kim 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.1

This paper introduces a new U.S. ultra-wideband(UWB: 3.1~10.6 GHz) 1:2 power divider based on a single section Wilkinson type configuration. The divider provides very flat in-band power splitting, high isolation, low insertion loss, sharp roll-off bandpass filtering, and DC blocking characteristics. The circuit consists of a λ/4 Y resonator, three capacitively coupled λ/2 short-circuited lines, and a resistor between the two output ports. The circuit structure was simulated with ADS and HFSS, and realized with low-temperature co-fired ceramic(LTCC) green tape, which has a dielectric constant of 7.8. |S11| better than 10 ㏈, |S21| and |S31| less than 3.2 ㏈, with both |S22| and |S32| measured as better than 12 ㏈ for the whole UWB band. Measurement results agree closely with HFSS simulation results. The power divider has a compact size of 4×9×0.6 ㎣.

LOW insertion Loss Multilayer Capacitively Loaded Step-Impedance Miniaturized UWB Bandpass Filter

Thai Hoa Duong,김인석 경희대학교 산학협력기술연구원 2008 산학협력기술연구논문집 Vol.14 No.-

In this paper, a low insertion loss interdigital bandpass filter with capacitively loaded stepped impedance resonators (SIR) in Low Temperature Co-fired Ceramic (LTCC) technology is introduced. By using SIR and capacitive loading structures based on E_(r)= 41. 77 substrates, a wideband interdigital bandpass filter has been realized for the frequency range from 3.1 GHz to 4.8 GHz. Measurement shows insertion loss less than 0.8 dB, return loss better than 15 dB in the pass band with the center frequency at 3.95 GHz and bandwidth ratio of 43%. The filter has a size of 2.15 x 2.6 x O.85mm^(3). 본 논문에서는, Low Temperature Co-fired Ceramic (LTCC) 기술을 이용하여 capacitively loaded stepped impedance resonators (SIR) 를 갖는 낮은 삽입손실 인터디지털 대역통과 필터를 소개한다. E_(r)= 4 1. 77을 기반으로 하는 SIR과 capacitive loading 구조를 이용함으로써,광대역 인터 디지털 대역통과 필터는 3.1 에서 4.8 GHz 의 주파수 범위에 대해서 실현이 된다. 측정값은 중심주파수 3.95GHz를 갖는 통과 대역에서 삽입 손실이 0.8 dB 보다 작고,반사 손실은 15 dB 이상이고,43% 의 대역폭 률 을 보여준다. 필터의 크기는 2.15 x 2.6 x 0.85㎣ 이다.

A Modified λ₀/4 Short-Circuited Stub Bandpass Filter for UWB Applications Utilizing LTCC Technology

DUONG, Thai Hoa,LEE, Kye San,KIM, Ihn S. The Institute of Electronics, Information and Comm 2010 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.93 No.5

<P>In this paper, we utilize low temperature co-fired ceramic technology (LTCC) to realize a modified short-circuited stub bandpass filter suitable for ultra-wideband (UWB) applications. By modifying the conventional short-circuited stub bandpass filter structure with stubs and connecting lines of lower characteristic impedances, the number of stubs has been reduced from 5 to 2 on a high dielectric constant substrate (ε<I><SUB>r</SUB></I>=40). A wireless local area network (WLAN) stopband in the frequency range of 5.15 to 5.825GHz has been inserted into the filter characteristic using three short-circuited coupled lines. The filter is fabricated and measurement results show that it has an insertion loss less than 1.0dB and return loss better than 10dB in the pass bands. A bandwidth ratio of 109.49% has been achieved. Measurement results agree well with simulation results. The dimensions of the filter are 4×8×0.57mm<SUP>3</SUP>.</P>

저특성 임피던스의 4 단락 스터브 기술을 이용한 WLAN 저지 대역을 가지는 UWB BPF

Duong Thai Hoa,주효석,김인석 한국전자파학회 2009 한국전자파학회논문지 Vol.20 No.4

본 논문에서는 기존의 4 단락 스터브 대역 통과 필터의 특성을 개선하여 LTCC(Low Temperature Co-fired Ceramic)을 이용하여 UWB(Ultra Wideband) 응용에 적합한 필터 기술을 소개한다. 높은 유전 상수의 기판(40)상에 기존의 4의 단락 스터브 대역 통과 필터 기술을 적용하기 위하여 기존의 필터와는 다르게 낮은 특성 임피던스 선로를 이용하여 결과적으로 스터브의 수를 다섯 개에서 두 개로 감소시켰다. 또한, 3개의 단락 결합 선로를 이용해서 5.15 GHz에서 5.825 GHz의 주파수 범위에서 WLAN(Wireless Local Area Network) 저지 대역을 특성 내에 삽입하였다. 본 필터는 통과 대역에서 1 dB 미만의 삽입 손실과 10 dB 이상의 반사 손실을 갖는 것으로 측정되었고, 109.49 %의 대역폭 율이 달성되었다. 측정 결과는 시뮬레이션 결과와 잘 일치한다. 필터의 크기는 4×8×0.57 ㎣이다.

New Elliptic Function Type UWB BPF Based on Capacitively Coupled <tex> $\lambda/4$</tex> Open T Resonator

Thai Hoa Duong,Kim, I.S. IEEE 2009 IEEE transactions on microwave theory and techniqu Vol.57 No.12

<P>This paper introduces two new circuit structures for European and U.S. ultra-wideband (UWB) bandpass filters (BPFs) with sharp roll-off characteristics. The circuit structures consist of capacitively coupled three parts in stripline structure, a λ/4 open T resonator, a λ/4 short-circuited line, and input and output lines. We show first that ultra wide bandpass property is basically obtained from the T resonator with a capacitively coupled λ/4 short-circuited line, which provides two attenuation poles at lower and upper cutoff frequencies. Two identical capacitively coupled input/output lines, which can be λ/4 length open ends or λ/2 length short ends, with the T resonator are adopted to suppress lower and higher frequency components outside of the passband. There is coupling between the input and output lines providing two additional transmission zeros in the lower and upper transition bands of the filter. Since the coupling between the T resonator with the λ/4 short-circuited line and the input/output lines limits the bandwidth of the filter to the European UWB band, both the λ/4 short-circuited line and the input/output lines are inserted between the two stacked T resonators for the U.S. UWB band. The filter structures are simulated with ADS and HFSS and realized with low-temperature co-fired ceramic (LTCC) green tape which has the dielectric constant of 7.8. Measurement results agree well with HFSS simulation results.</P>

Steeply Sloped UWB Bandpass Filter Based on Stub-Loaded Resonator

Thai Hoa Duong,Kim, I S IEEE 2010 IEEE microwave and wireless components letters Vol.20 No.8

<P>This letter introduces an ultrawideband (UWB) bandpass filter (BPF) with very sharp roll-off characteristics in stripline structure for the U.S. band (3.1-10.6 GHz). The UWB characteristic is basically obtained from capacitive coupling between a main line and a λ/2-length stub-loaded resonator. The stub-loaded resonator consists of λ/8 short-circuited and open-circuited stubs at the center of the λ/2 line. The two stubs provide two attenuation poles at lower and upper cutoff frequencies. For input and output lines, two λ/4 identical capacitively coupled lines have been installed to suppress the unwanted signals in the lower and upper stopbands. The filter has been designed with two transmission zeros at 2.4 and 11.1 GHz to provide 81- and 86-dB/GHz slopes in the lower and upper transition bands, respectively, and realized with low-temperature co-fired ceramic (LTCC) green tape that has the dielectric constant of 7.8. Measurement results agree well with HFSS simulation results. Insertion loss less than 1.1 dB and return loss better than 14 dB in the whole passband have been measured. The group delay at the center frequency is 0.26 ns, and the group delay variation within the passband is less than 0.5 ns. The size of the filter is 6 × 18 × 0.6 mm<SUP>3</SUP>.</P>

New UWB BPF with Steep Selectivity Based on T-Resonator and Capacitively Coupled λ/4 and λ/2 Line Sections

Thai Hoa Duong,Ihn Seok Kim 한국전자파학회JEES 2009 Journal of Electromagnetic Engineering and Science Vol.9 No.3

In this paper, two new circuit structures for European and U.S. ultra-wide band(UWB) bandpass filters(BPFs) with sharp roll-off characteristics are introduced. We show first that the ultra-wide bandpass property is obtained from a λ/4 open T resonator with a capacitively coupled λ/4 short-circuited line, which provides two attenuation poles at lower and upper cutoff frequencies. Then, two identical capacitively coupled input/output lines, which can be λ/4-length open ends or λ/2-length short ends, with the T-resonator, are adopted to suppress lower and higher frequency components outside of the pass band. There is coupling between the input and output lines providing two additional transmission zeros in the lower and upper transition bands of the filter. Since the coupling between the T-resonator with the λ/4 short-circuited line and the input/output lines limits the bandwidth of the filter to the European UWB band, both the λ/4 short-circuited line and the input/output lines are inserted between the two stacked T-resonators for the U.S. UWB band. The filter structures are simulated with ADS and HFSS and realized with low-temperature co-fired ceramic(LTCC) green tape which has the dielectric constant of 7.8. Measurement results agree well with HFSS simulation results.

저특성 임피던스의 λ ₀/4 단락 스터브 기술을 이용한 WLAN 저지 대역을 가지는 UWB BPF

동 타이 호아(Duong Thai Hoa),주효석(Hyo-Suk Joo),김인석(Ihn-Seok Kim) 한국전자파학회 2009 한국전자파학회논문지 Vol.20 No.4

본 논문에서는 기존의 λ ?/4 단락 스터브 대역 통과 필터의 특성을 개선하여 LTCC(Low Temperature Co-fired Ceramic)을 이용하여 UWB(Ultra Wideband) 응용에 적합한 필터 기술을 소개한다. 높은 유전 상수의 기판( ε r = 40)상에 기존의 λ ?/4의 단락 스터브 대역 통과 필터 기술을 적용하기 위하여 기존의 필터와는 다르게 낮은 특성 임피던스 선로를 이용하여 결과적으로 스터브의 수를 다섯 개에서 두 개로 감소시켰다. 또한, 3개의 단락결합 선로를 이용해서 5.15 ㎓에서 5.825 ㎓의 주파수 범위에서 WLAN(Wireless Local Area Network) 저지대역을 특성 내에 삽입하였다. 본 필터는 통과 대역에서 1 ㏈ 미만의 삽입 손실과 10 ㏈ 이상의 반사 손실을 갖는 것으로 측정되었고, 109.49 %의 대역폭 율이 달성되었다. 측정 결과는 시뮬레이션 결과와 잘 일치한다. 필터의 크기는 4×8×0.57 ㎣이다. In this paper, we introduce a modified short-circuited stub bandpass filter suitable for ultra-wideband(UWB) applications utilizing low temperature co-fired ceramic(LTCC) technology. By modifying the conventional short-circuited stub bandpass filter structure with stubs and connecting lines of lower characteristic impedances, the number of stubs has been reduced from 5 to 2 stubs on a high dielectric constant substrate( ε r =40). A wireless local area network (WLAN) stopband in the frequency range of 5.15 to 5.825 ㎓ has been inserted into the filter characteristic using three short- circuited coupled lines. The filter has been measured with an insertion loss less than 1.0 ㏈ and return loss better than 10 ㏈ in the pass bands. A bandwidth ratio of 109.49 % has been achieved. Measurement results agree well with simulation results. The dimensions of the filter are 4×8×0.57 ㎣.