• KIEE International Transactions on Electrophysics and Applications
• /
• v.4C no.6
• /
• pp.288-294
• /
• 2004

In this paper, a ceramic antenna and diplexer are designed for dual-band handset ap plications. Basically, the antenna is designed by using the meander line configuration. The diplexer presented in this paper is composed of both low- and high-pass filters. We have designed the low- and high-pass filters with attenuation poles to improve the attenuation performances of the diplexer. The attenuation poles are located at each rejection frequency region so as to improve the shrinkage characteristic of the diplexer. In order to accomplish the volume effectiveness, the antenna and the diplexer have been designed and fabricated in a multi-layer structure. The diplexer designed with a multi-layer structure has inductors and capacitors, which are implemented by LTCC (Low Temperature Co-fired Ceramics) process technique. Design of the multi-layer antenna and diplexer has been achieved by employing the full 3-D EM simulation. The designed antenna and diplexer offer excellent return loss and broadband performances with highly isolated rejection performance.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.17 no.1
• /
• pp.57-63
• /
• 2014

In this paper, we have proposed a wide band antenna for manpack SDR(Software Defined Radio). The proposed antenna consists of feeding post, flexible gooseneck and two radiating elements composed of a upper and lower radiators. The upper radiator has a longer electrical length than the lower radiator in order to operate in the lower frequency. Also, the resonant frequency and impedance characteristics of the antenna can be adjusted independently for two radiators. Therefore, the proposed antenna can be achieved wide impedance bandwidth by the combination of two independent resonance modes. To analyze the characteristics of the antenna in the design process is employed the equivalent circuit theory and EM(Electro-Magnetic) simulation. The measurement results show that the proposed antenna have the sufficient wide bandwidth, above -3.4dBi of the gain and fairly good radiation pattern over the wide bandwidth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.12
• /
• pp.1069-1077
• /
• 2011

In this paper, a design and fabrication of a miniaturized 2.5 GHz 8 W power amplifier using selectively anodized aluminum oxide(SAAO) substrate are presented. The process of SAAO substrate is recently proposed and patented by Wavenics Inc. which uses aluminum as wafer. The selected active device is a commercially available GaN HEMT chip of TriQuint company, which is recently released. The optimum impedances for power amplifier design were extracted using the custom tuning jig composed of tunable passive components. The class-F power amplifier are designed based on EM co-simulation of impedance matching circuit. The matching circuit is realized in SAAO substrate. For integration and matching in the small package module, spiral inductors and single layer capacitors are used. The fabricated power amplifier with $4.4{\times}4.4\;mm^2$ shows the efficiency above 40 % and harmonic suppression above 30 dBc for the second(2nd) and the third(3rd) harmonic at the output power of 8 W.

• Journal of Advanced Navigation Technology
• /
• v.26 no.3
• /
• pp.160-165
• /
• 2022

In this paper, we have proposed a magnetic resonant 6.78MHz WPT(wireless power transfer) technique which can be applied to a fixed transmitter and a receiver of varying relative distance and coil alignment, Power transmission characteristics are studied with the relative distance and misalignment ration of coil area between the transmitting and receiving coils. The coils are designed with the size of 60×80mm² by direct feeding method, and the characteristics are derived with the maximum relative distance of 50mm and horizontal area misalignment state of 0-40mm misalignment of coil center axis in the XY plane. The power transmission characteristics are compared between the 3D EM simulation and the measured data, and the power transmission shows larger than -3dB performance with the vertical distance of up to 30mm and 50% area misalignmment ratio. This work showsthe transmission characteristics according to relative distance and misalignment state between the cols and that direct feeding has advantage for the short relative distance and small misalignment ratio.