• 한국전자파학회지:전자파기술
• /
• 제2권2호
• /
• pp.3-10
• /
• 1991

GaAs FET초고주파 증폭기의 DC 블럭용으로 사용되는 칩 커페시터 대신 DC블럭 및 임피던스 변환 성질을 가진 DC block/transformer(비대칭 2선 마이크로스트립 선로 및 까지낀 3선 마이크로스트립 선로)를 사용한 초고주파 증폭기의 새로운 구성 방법을 제시하였다. 새로운 구성을 갖는 초고주파 증폭기의 대역 특성은 평탄하며 대역폭이 3.5(BHz)인 광대역 특성을 얻으 수 있었다. 초고주파 증폭기에 사용된 깍지낀 3선 마이크로스트리 결합 선로는 DC블럭 기능과 함께 임피던스 정합 역할을 할 수 있는 큰 장점을 가지고 있다.

• 한국통신학회논문지
• /
• 제24권6B호
• /
• pp.1142-1148
• /
• 1999

본 논문에서는 Ku-밴드의 마이크로파 대역에서 위상배열 안테나에 사용 가능한 결합선로를 이용하여 위상천이기에서 기존에 고려하지 않았던 주파수에 따른 분산특성을 전파(Full-wave) 해석방법인 SDA(Spectral Domain Approach)를 사용하여 정확히 해석하였다. 또한 비대칭 결합선로를 사용하는 위상천이와 유전치 덮개층이 부가된 위상천이기의 설계를 제안하였다. 현재 사용되고 있는 대칭 결합선로를 이용한 쉬프만 위상천이기와 비교하여, 이에 대한 위상응답의 특성변화에서 통과대역의 위상편차가 줄고 대역폭이 확대되어 광대역 특성이 개선되는 것을 이론적으로 해석하고 실험을 통하여 검증하였다.

• Journal of electromagnetic engineering and science
• /
• 제13권1호
• /
• pp.34-37
• /
• 2013

This paper presents a novel ultra-wideband (UWB) antenna that rejects narrow and broad bands and is suitable for wireless communications. The base of the proposed antenna has a circular patch that can cover the UWB frequency range (3.1~10.6 GHz). The interference issues caused by co-existence within the UWB operation frequency are overcome by a design that uses a parallel-coupled asymmetric dual-line with a circular monopole antenna. The proposed antenna showed a stable radiation pattern, realized gain and reflection coefficient lower than -10 dB across the UWB operation bandwidth except for 5.15~5.85 GHz and 7.25~8.4 GHz. The fabrication, simulation, and measurement results obtained for the proposed antenna were in good agreement with the expected values.

• Journal of Advanced Marine Engineering and Technology
• /
• 제37권7호
• /
• pp.752-759
• /
• 2013

This paper presents a method for analyzing and designing an extremely miniaturized planar ring hybrid, using the combination of parallel and diagonally shorted coupled lines. In contrast to conventional miniaturized coupled line filters, it is proven that the required electrical length of transmission line can be largely reduced to even a few degrees, not only effectively suppressing the spurious passband but also approximately maintaining the same characteristic around the stable center frequency. A ring hybrid filter at center frequency of 1 GHz was fabricated on the FR4 epoxy glass cloth copper-clad plat (CCL) PCB substrate. The insertion loss of a ring hybrid filter with the die area of $30mm{\times}30mm$ is -4.68 dB. Simulated results are well agreed with the measurements.

• 조명전기설비학회논문지
• /
• 제20권9호
• /
• pp.40-44
• /
• 2006

This study investigated a new tuneable bandpass filter based on coplanar waveguide coupled line structure, and using the varactor diode for tuning the center frequency of the filter. The filter was designed by a commercial simulator and had a tuning range of 180[MHz] from 0.95[GHz] to 1.13[GHz]. The filter acceptable values regarding the insertion loss was less than 3[dB] and its return loss greater than 12[dB]. The figure of merit of the implemented tuneable filter increased with the reverse bias voltage up to 14[V] on the varactor diode. The proposed filter has a promising future as it can be used in integration processes and in various materials as substrate.

• ETRI Journal
• /
• 제31권3호
• /
• pp.324-326
• /
• 2009

We present the design of a compact microstrip lowpass filter with a wide stopband which is up to ten times the cutoff frequency. The filter is based on a coupled-line configuration and shunt open stubs. The open stubs create additional transmission zeros, which are used to extend the stopband of the filter without any additional components or cascaded units. A prototype lowpass filter with a 3 dB cutoff frequency of 0.428 GHz and a 15 dB stopband extended up to 4.77 GHz is fabricated to validate the theoretical predictions.

• 전자공학회논문지D
• /
• 제34D권10호
• /
• pp.24-31
• /
• 1997

A new design method of stable RF power amplifier using 3dB coupled line is proposed in this thiesis. The proposed method of broadband matching consist of resistive matching circuits at low frequency and lossless matching circuits at microwave band. This design method increase the stability of an amplifier and is suitable for interstage matching. When high power amplifier is designed using this method for PCS base transceiver station, the measured resutls show thst the gain of 18.5dB, and 9W (39.5dBm) output power. We use motorola's MRF6401 for medium power and MRF 6402 for large power and cascaded them.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
• /
• pp.153-156
• /
• 2002

In this paper, we have designed a small size lumped/distributed hybrid element directional coupler using parallel coupled-line theory. a hybrid lumped equivalent circuit for a conventional parallel directional coupler is proposed. The equivalent circuit and design formula for the presented lumped element coupler are derived based on the even- and odd-mode properties of a parallel-coupled line. By using the derived design formula, we have extracted design parameters and designed the 3㏈ and 10㏈ small size lumped element directional couplers at the center frequency of 2Ghz. Excellent agreements between design theory and simulation on the designed directional couplers show the validity of this paper.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제55권4호
• /
• pp.217-222
• /
• 2006

A distributed balun such as Marchand balun typically shows good phase and amplitude balances, but its size is somewhat large especially in lower frequency band. In contrast, a lumped balun has compact size but its performance is not good compared with that of a distributed one. In this paper the distributed-coupled line can be reduced effectively by using the lumped-distributed implementation. Designed balun has two coupled line of each ${\lambda}/72$ and shows magnitude balance of 0.05 dB, phase balance of $0.7^{\circ}$ in passband. Balanced-type filter is designed using balun and it has insertion loss of 8 dB, return loss of 7 dB, magnitude balance of 0.2 dB, and phase balance of $1.2^{\circ}$ in passband.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제53권11호
• /
• pp.577-582
• /
• 2004

In this paper, lumped equivalent circuits for a conventional parallel directional coupler are proposed. This equivalent circuits only have self inductance and self capacitance, so we can design exact lumped equivalent circuit. The equivalent circuit and design formula for the presented lumped element coupler is derived based on the even- and odd-mode properties of parallel-coupled line. By using the derived design formula, we have designed the 3dB and 4.7dB MMIC couplers at the center frequency of 3.4GHz and 5.6GHz respectively. Measurements for the designed MMIC directional couplers show at 4dB and 5.2dB-coupling value at the center frequency of 3.4GHz and 5.6GHz. Excellent agreements between simulation results and measurement results on the designed directional couplers show the validity of this paper