Resonator-based analysis of the combination of mobile handset antenna and chassis

Abstract

Abstract-In this paper, the performance of the mobile phone handset antenna-chassis combination is analyzed based on an approximate decomposition of the waves on the structure into two resonant wavemodes: the antenna-element wavemode and the chassis wavemode. A double resonator equivalent circuit model is presented and used to estimate the impedance bandwidth and the respective distribution of radiation losses with typical parameter values at 900 and 1800 MHz. It is noticed that at 900 MHz, the radiation losses by the antenna element wavemode represent typically less than 10% of the total power. Thus, the antenna element works mainly as a matching element, which couples to the lowresonant wavemode of the chassis. At 1800 MHz, the contribution of the antenna element wavemode is larger. By enhancing the coupling and by tuning the chassis resonance, it is possible to obtain an impedance bandwidth of over 50% (6-dB return loss) at both at 900 and 1800 MHz. The results given by the equivalent circuit study are fully supported by those of three-dimensional phone-model simulations, including calculation of the SAR and efficiency values. In prototyping, the 6-dB bandwidth of 5.5% was obtained at 980 MHz with a nonradiating coupling element with a volume of 1.6 cm 3 on a 120-mm-long chassis.

Carrier Aggregation Compatible Mimo Antenna for Lte Handset

“…Decreasing low-band efficiency is an expected result, as at frequencies below 1 GHz, the chassis contributes the most to overall handset radiation [12]. In the current design, the main and diversity antennas both couple to the same chassis, and this coupling reduces efficiency.…”

“…The main antenna features a combination of aperture-matched, fed, and parasitic radiators, and in the current work it is referred to as a Combined Parasitic-coupled, Aperture-Matched (CPAM) antenna. A more conventional, simple Capacitive Coupling Element (CCE) [11,12] is used as the diversity antenna. The CPAM antenna is based on a recent design presented in [13], and the design of this work is significantly simpler and more straightforward compared to the previous work; both the number of matching components and feeds have been reduced by 50%.…”

Multiband Folded Loop Antenna for Smart Phones

“…Center resonance frequency in the low band is slightly influenced by ground plane length. Traditional PIFA has a quarter-wavelength shorted patch and a finite ground plane [10]. The ground plane acts as part of a resonator in the lower band.…”

“…This is necessary, especially as the mobile device is quite small. However, the current variation due to the device being hand-held and the resulting body proximity effect degrades antenna performance since the resonating currents are spread out over the system ground plane [1,10]. To avoid degrading antenna performance, a printed loop antenna is another candidate for the mobile phone since the current induced on the ground plane is small [11][12][13][14][15][16][17].…”

A Compact Quad-Band Pifa by Tuning the Defected Ground Structure for Mobile Phones

“…The utilization of a slotted ground plane for broadening operational bandwidth of a small terminal antenna was described in [14][15][16].…”