Design of Wideband Balanced Folded-Arms Dipole Antenna for Mobile Handsets

Abstract

Investigations of a wideband balanced antenna for mobile handsets covering three bands-GSM1800, GSM1900, and UMTS-are presented. Balanced antennas have advantages in handset applications as they are less affected by juxtaposition with human tissue than unbalanced types. The antenna is a slotted planar dipole with its arms folded and not connected at their ends. The antenna is fed by a balanced voltage source. The antenna impedance was investigated using two different methods, including an S-parameter method and a mirror image method. For the purpose of antenna stability evaluation and power gain measurement, a wide bandwidth planar balun was adopted and modified to feed the antenna from an unbalanced source. For validation, prototypes of the antenna were fabricated and tested. The calculated and measured results in terms of return loss show good agreement and the results also show good wideband characteristics.

Miniaturized Balanced Antenna with Integrated Balun for Practical LTE Applications

“…Moreover, this present antenna has achieved a better efficiency in contrast to [16], [23]. Furthermore, it accomplishes an improved gain compared with works in [18,22,23,25,26].…”

“…1, one can observe these available balanced antennas can only cover either the major ex-isting mobile bands or/and UWB spectrum, for example: antenna design in [17] can only cover GSM900, the antenna geometry in [18] is capable to work for GSM1800, an antenna operating over the GSM900/1800 was proposed in [19]; whereas [16], [20] proposed antennas to operate in WLAN, authors in [22] proposed balanced antenna structure covering GSM and UMTS, while [23] designed a balanced antenna to operate in GSM and WLAN, and authors in [24] offered balanced antennas that work in the full operation of three mobile radio bands of GSM900/1800, PCS/1900 and UMTS/2200.…”

“…By compromising the bandwidth, antenna size and frequency bands, some approaches were proposed by previous author's works [18], [20][21][22][23][24] and dual-band functional operation, as shown in Tab. 1.…”

“…To exploit this beneficial property, a number of mobile phone balanced antenna structures operating in dualband, multiband and wide band have been recently studied [16][17][18][19][20][21][22][23][24][25][26][27]. Tab.…”

MIMO Multiband Balanced Antenna Design for Wireless Communication

“…For low gain mobile terminal antennas ρ ≤ 2 and ρ ≤ 3 [16]. Preferably, in case of no transmission line mismatch.…”