• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.128-134
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• 2010

In this paper, a high-power 20-way stripline power divider with low insertion loss and low side lobe level is successfully designed, fabricated and measured as a feed network for an S-band linear array antenna having Dolph-Chebyshev current distribution which has a narrow beam width and very low side lobe level (SLL). The 20-way stripline power divider consists of an 8-way power divider, three 4-way power dividers and three ring hybrids. It utilizes a T-junction structure as a basic element for power dividing. Notches and modified input/output N-to-stripline transitions are used for improving insertion loss and return loss. The fabricated power divider shows insertion loss less than 0.3 ㏈ and rms phase mismatch less than 8o in the full bandwidth. A final 40-way power divider is synthesized by combining symmetrically two 20-way power dividers and is expected to have SLL over 40 dB, based on the measured results of the 20-way power divider.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.3
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• pp.280-288
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• 2009

In this paper, a high-power and low-loss stripline 10-way power divider is designed and fabricated fur the feed network of an S-band linear array antenna with Chebyshev current distribution which has a narrow beam width and low side lobe level(SLL) of 35 dB or more. The unit cell of the power divider is based on a T-junction power divider and the whole divider is comprised of the cascaded unit cells. The multi-stage impedance transformer and modified ring hybrid are used in designing the power divider for performance improvement. And the reflection loss and insertion loss are improved by modifying a connector structure for a coaxial-to-stripline transition.

• Journal of the Korean Institute of Telematics and Electronics
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• v.14 no.5
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• pp.7-14
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• 1977

Conventionally, a TIVT has been used for high power amplification in the microwave frequency range. However, an ultra-high-power amplifier in the 2GHz range has successfully been designed and fabricated employing high power transistors developed recently and available commercially. In the design of the amplifier, a balanced-pair configuration is adopted in order to obtain very high microwave power, and a good impedance matching is achieved by making use of microstripline techniques. For the RF power divider as well as combiner, an approach of stripline directional coupler isadopted because of its easiness in fabrication. The coupler so designed and fabricated indicates a satisfactory performance as a quadrature hybrie coupler. Measurements on the amplifier developed for an immediate commercial application also exhibit excellent overall performance characteristics RF power output, 14 watts, gain 14dB, frequency bandwidth, 160MHz, effciency 40%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1160-1164
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• 2008

This paper presents an wideband stripline balun. And, the proposed balun is composed of one power divider and two phase converters on stripline substrate. The target characteristics of the proposed balun is the combination loss of below -0.05 dB, an amplitude imbalance of ${\pm}0.5\;dB$ and a phase imbalance of $180{\pm}10$ degrees, with the reflection coefficient(S11) of below -10 dB over frequencies ranging from 500 to 1500 MHz. The fabricated balun occupies the area of $12(W){\times}220(L){\times}2.3(T)\;mm3$. Experimental measurement shows that the fabricated balun has an amplitude imbalance of ${\pm}0.7\;dB$, a phase imbalance of $180{\pm}8$ degrees and an insertion loss of about -2 dB with the reflection coefficient(S11) of below -10 dB over frequencies ranging from 500 to 1,500 MHz.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.95-100
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• 2007

In this paper, a twice folded TEM horn antenna for 70 kV impulse high power system is proposed. The length reduction of 50 % is achieved by folding a conventional TEM horn antenna twice. The array elements are fed by the stripline power divider using the Chebyshev transformer. The power divider feeds four TEM horn antenna elements with an in-phased uniform power, and it covers a wide bandwidth ($150\;MHz\;{\sim}\;768\;MHz$, VSWR<2.0). Considering the air breakdown at peak 70 kV impulse, the proposed antenna maintains the 25 mm gaps between conducting plates. The dimension of the twice folded horn antenna is $1730\;{\times}\;1600\;{\times}\;300$ (mm3), and the operating frequency is from 152 MHz to 750 MHz under 10 dB return loss. The peak gains are measured from 6.77 dBi to 10.70 dBi at $400\;MHz\;{\sim}\;750\;MHz$.

• Journal of electromagnetic engineering and science
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• v.12 no.4
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• pp.254-259
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• 2012

This paper presents a closely spaced two-element folded-dipole-driven quasi-Yagi array with low mutual coupling between adjacent elements. The antenna utilizes a T-junction power divider as the feeding network, with an input impedance of $50{\Omega}$. A microstrip-stub is added to the ground plane in the middle of the two elements to improve the mutual coupling characteristics. The folded dipole driver is connected to a $50{\Omega}$ microstrip line via a broadband microstrip-to-coplanar stripline transition with a quarter radial stub. A mutual coupling of less than -22 dB is measured between two folded-dipole-driven quasi-Yagi antennas with a center-to-center spacing of 30 mm ($0.55{\lambda}_0$ at 5.5 GHz). The proposed quasi-Yagi array yields a measured bandwidth of 4.75~6.43 GHz for the -10 dB reflection coefficient and a gain of 6.14~7.12 dBi within the bandwidth range.