The widely-used measurement methods for conductivity of non-magnetic metals are van der Pauw method, Two Point Probe method and Eddy Current method. Among them a more simpler and easier method is the Eddy Current method and an instrument using the method is a Conductivity Meter which can measure a conductivity by contacting its probe on a sample surface. However, conductivity standards are essentially needed to confirm the meter’s performance or to calibrate it. In this study, six kinds of the standards which are made of Cu, Al-1, Al-2, brass, Zn and SUS-316 are developed and conductivity ranges for the standards are 2.27 %IACS ~ 101.6 %IACS with measurement uncertainty of less than 0.3 %.

van der Pauw method를 이용한 금속 도전율 인증표준물질 개발

A new and significantly small guided and resonant structure is suggested to take over bulky metallic hollow waveguides used in military satellite transceivers. Below Ku-band, the conventional waveguides resulting in quite heavy transceivers will be replaced by the low profile SIW(substrate integrated waveguide) structures that are distinguished from the others in that the suggested ones have much lower cut-off frequencies by the circuital configuration of DNG(dobule negative) constitutive parameters and become even smaller than the other SIWs. The design scheme is validated by the circuit and full-wave simulations from the guided, resonant, and coupled structures. Besides, a bandpass filter as the suggested coupled structure is fabricated with a cheap substrate in a low-budget fabrication process and its frequency response is measured as verification of the purpose of the design.

군위성 송수신기용 기존 금속 도파관을 대체하는 dng형 기판적층 도파관 공진기의 설계

This paper proposes a compact dual-band 3-way power divider that helps lowering the weight of a transceiver for the L-band or multi-purpose satellite communication. Instead of the multi stages or tapering which ends up with loss accumulation and size-growth, the non-linear dispersive phases from the metamaterial CRLH(composite right and left-handed) properties are obtained by the accurate formulation and implemented by the short transmission line segments. Firstly, the CRLH dual-band two-way unequal power divider and equal power divider are separately designed. And then, the input of the two-way equal power divider is plugged in the output port of the unequal one, and the entire geometry is slightly adjusted for the desirable performance. The circuit analysis and full-wave simulation are used to predict the frequency responses and validated by the measurement of the prototype. Besides, the size-reduction effect is addressed.

Design of a Metamaterial-Based Compact Dual-Band 3-way Power Divider for Lighter L-band Military Satellite Transceivers

According to an embodiment, provided are compact and lightweight duplexers for maintaining the performance of SIW channel filters of zero-order resonance metal-material structure which comprises a ground layer; a dielectric layer on the ground layer; a first metal layer which is disposed on the dielectric layer and includes a first metal portion connected to a first via and a second via disposed in parallel with the ground layer, a second metal portion connected to a third and fourth vias disposed in parallel with the ground layer, and a common portion disposed between the first and the second metal portions; and a second metal layer which is disposed within the dielectric layer and includes a first connection metal portion having a first pass band by being connected to the first metal portion and a first auxiliary via and a second connection metal portion having a second pass band by being connected to the second metal portion and a second auxiliary via.

Compact and Light Duplexers with the SIW-based layered waveguide structure for satellite communications terminals

This paper proposes a novel compact MIMO antenna which has miniaturized radiators and their row correlation coefficient, working for the LTE mobile communication, and its SAR is observed. Each of the proposed radiators has a shape of staircase and the bandwidth is twice larger than the conventional PIFA as 600MHz(21%) in 2.5 GHz - 3.15 GHz. And the area of the radiators is 16.5mm ⅹ 9.7mm proper for a handheld device. Also, by adding a planar mushroom decoupling structure between the radiators, the isolation is improved. The design has been carried out using the commercial full-wave time-domain EM solver and the finalized MIMO antenna has the return loss less than -10 dB in the LTE band, the isolation better than 20 dB and the efficiency more than 90% with the gain of 4.3 dB. Regarding the SAR of the antenna, it is observed that the average SAR value of 1g is estimated as 1.37W/Kg, which is lower than the SAR standard.

강경석

Papers

군위성 송수신기용 기존 금속 도파관을 대체하는 dng형 기판적층 도파관 공진기의 설계

Design of a Metamaterial-Based Compact Dual-Band 3-way Power Divider for Lighter L-band Military Satellite Transceivers

Compact and Light Duplexers with the SIW-based layered waveguide structure for satellite communications terminals

Sar규격을 만족하는 우수한 격리도의 소형 계단구조 광대역 mimo 안테나