2개 분기선로와 수직 선로를 갖는 WLAN/WiMAX 시스템에 적용 가능한 삼중대역 안테나 설계 및 제작

Design and Manufacture of Triple-Band Antennas with Two Branch Line and a Vertical Line for WLAN/WiMAX system applications

Abstract

본 논문에서는 WLAN과 WiMAX 대역에서 동작 가능하도록 삼중대역 안테나를 설계 제작 및 측정하였다. 마이크로스트립 선로를 사용하여 급전하였으며 패치면에 두 개의 분기된 선로를, 그리고 접지면에 사각슬릿을 삽입하여 삼중대역 특성을 갖도록 설계하였다. 그리고 임피던스 대역폭의 특성을 개선하기 위해 접지면에 수직 스트립 선로를 추가하였다. 제안된 안테나는 유전율 4.4 그리고 두께 1.0mm인 유전체 기판 위에 $18.0mm(W1){\times}37.3mm$ (L4+L5+L7) 의 크기로 설계되었다. 제작 및 측정 결과로부터 2.4/2.5 GHz에서는 480 MHz (2.32~2.80 GHz), 3.5 GHz 대역에서는 810 MHz (3.22 ~ 4.03 GHz), 그리고 5.0 GHz 대역에서는 1,820 MHz (5.05 ~ 6.87 GHz)의 대역폭을 얻었다. 또한 측정된 3D 방사패턴을 제시하였으며 요구되는 주파수 대역에서 측정된 이득값을 제시하였다.

In this paper, an antenna applicable to WLAN and WiMAX frequency bands is designed, fabricated, and measured. The proposed antenna is designed to have two branch strip line in the patch plane and a rectangular slit in the ground plane based on microstrip feeding for triple band characteristics and added a vertical strip in the ground plane to enhance impedance bandwidth characteristics. The proposed antenna is designed on a substrate with a relative permittivity of 4.4, a thickness of 1.0 mm, and has a size of $18.0mm(W1){\times}37.3mm$ (L4+L5+L7). From the fabricated and measured results, impedance bandwidths of 480 MHz (2.32 to 2.80 GHz) for 2.4/2.5 GHz band, 810 MHz (3.22 to 4.03 GHz) for 3.5 GHz band, and 1,820 MHz (5.05 to 6.87 GHz) for 5.0 GHz band were obtained based on the impedance bandwidth. Measured 3D pattern and gains are displayed.

Fig. 1 The geometry of the proposed WLAN/WiMAX antenna

Fig. 2 Return loss characteristic of the effect of the W₄.

Fig. 3 Return loss characteristic of the effect of the L₃.

Fig. 4 Return loss characteristic of the effect of the L₅.

Fig. 5 Return loss characteristic according to the withand with out slit in the ground.

Fig. 6 The surface current density of proposed antenna (a) 2.59 GHz, (b) 3.33 GHz, and (c) 5.51 GHz.

Fig. 7 Fabricated of propose antenna (a) Front view, (b) Back view.

Fig. 8 The simulated and measured return loss results

Fig. 9 3D radiation pattern of 2.4 GHz

Fig. 10 3D radiation pattern of 3.6 GHz

Fig. 11 3D radiation pattern of 5.20 GHz

Fig. 12 3D radiation pattern of 5.80 GHz

Fig. 13 Measured peak and average gains of the designed antenna

Table. 1 Results of simulation : W4

Table. 2 Results of simulation : L3

Table. 3 Results of simulation : L5

Table. 4 Results of simulation with/without slit

Table. 5 Parameters of designed antenna

Table. 6 Results of measured return loss

Table. 7 Results of measured gain