Broadband series‐fed two dipole array antenna with an integrated balun for mobile communication applications

Abstract

A broadband series-fed two dipole array antenna is presented for mobile-base station applications covering the frequency bands for 2G, 3G, and long-term evolution systems. Two printed-strip dipole antennas with different lengths backed by a ground reflector are connected through a coplanar stripline, and an integrated balun consisting of a microstrip line and slot line is used to match the input impedance of the antenna to the 50 X feed line. Experimental results show that for a voltage standing wave ratio < 2, the proposed antenna presents a 49% bandwidth in the range of 1.7-2.8 GHz, a stable gain of 5.5-6.3 dBi, and a front-to-back ratio of 12-17 dB. Thus, the proposed antenna is suitable as a broadband base station element antenna, covering all mobile frequency bands.ABSTRACT: In this article, a novel wireless local area network (WLAN) frequency range monopole antenna is designed and manufactured for multi-input-multi-output (MIMO) applications. The proposed antenna consists of three pairs of folded L-shaped strips are placed side by side and printed on a dielectric substrate to generate triple-band operation which is suitable for WLAN applications. In this structure, each pair of L-shaped strips monopole antenna can create additional resonances within the WLAN range, which the desired resonant frequencies are obtained by adjusting the dimension of the folded L-shaped strips. The operating frequencies of the proposed antenna are 2.4/5.2/5.8 GHz which covers WLAN systems frequency range. Various configurations of array of this meander line structure monopole antenna for MIMO application are also studied. Prototypes of the proposed antenna have been constructed and studied experimentally. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and measured results are presented to validate the usefulness of this proposed small antenna structure for MIMO applications.

Tri-frequency Microcosmic Fractal Dipole Antenna with PBG Structure Used for 2G, 3G and 4G Systems

“…Dipole antenna has been applied widely in mobile communication systems, due to wide working band, low cost and whole direction radiation characteristic [6][7][8]. However, there are still some deficiencies to be overcome such as weak radiation ability and working only in single-frequency band [9][10][11].…”

Bandwidth Enhancement of Double-Dipole Quasi-Yagi Antenna Using Stepped Slotline Structure

“…Two parasitic strip directors (D r1 and D r2 ) are appended to the DDQYA above D 2 . An integrated balun between the MS line and the CPS line is implemented on the CPS line to match the input impedance of the antenna to the 50 Ω feed line, and the end of the MS line is shorted using a shorting pin at the feeding point [9]. The width of the slotline in the CPS line connecting R 0 and D 1 is w s1 , whereas that of the slotline in the CPS line connecting D 1 and D 2 is w s2 .…”

“…A reference double dipole QYA with uniform slot width in the CPS line and no directors is shown in Fig. 2(a) [9]. In this case, w s1 = w s2 = 0.7 mm, s 1 = s 2 = 36 mm, and l 2 = 54 mm.…”

Broadband Flat Gain Enhancement of Planar Double-Dipole Quasi-Yagi Antenna Using Multiple Directors

“…An impedance bandwidth of 9.2% (2.39-2.62 GHz) and a flat gain of 6-7 dBi were obtained by placing the radome above the patch antenna with some air spacing. A compact double-dipole QYA (DDQYA) consisting of two dipoles having different lengths, a truncated ground plane, and an integrated balun was introduced to achieve an impedance bandwidth of about 49% with a flat gain of 5-6 dBi in the band [6]. An elliptically tapered slot antenna with high and relatively-flat gain of 9.3-11.5 dBi operating in the frequency range of 2.65-12.90 GHz was proposed for ultra-wideband applications [7].…”

“…First, a DDQYA without multiple directors is shown in Figure 2(a). It is well-known that the frequency band moves toward the low frequency, and the gain in the low-frequency region increases, when the length of the second dipole of the DDQYA increases [6]. Based on this knowledge, the length ratio of D 2 to D 1 is set to r = l 2 /l 1 = 0.87 to enhance the gain in the low-frequency region.…”