Search

In Internet‐of‐things devices, to alleviate the performance degradation of the ground radiation antenna due to the large battery, two compact electromagnetic bandgap (EBG) unit cells are introduced between the ground radiation antenna and the battery. The ground radiation antenna is comprised a small loop‐type circuit that is designed within a 5‐mm × 5‐mm ground clearance for 2.4‐GHz WLAN applications. The compact EBG unit cell is a modified square split‐ring resonator that is designed by meandering‐line technology. The measurement results showed that the 3:1 VSWR impedance bandwidth of the ground radiation antenna increased from 30 to 90 MHz, and the average total efficiency increased from 19% to over 54% with and without the introduction of the EBG structure, respectively. [ABSTRACT FROM AUTHOR]

A wideband module antenna comprised of a small ground radiation antenna in the module and a parasitic radiation loop in the evaluation board is proposed. Unlike conventional ground radiation antennas, the ground radiation antenna in the module works as an exciter to the parasitic radiation loop, which further couples with the evaluation board as a radiator. Thus, a space‐saving antenna is obtained with wide bandwidth and easy tuning. Accordingly, dual resonance can be generated by tuning the resonant frequencies of the ground radiation antenna and the parasitic radiation loop equally. When measured, the antennas have wide bandwidths (2:1 voltage standing wave ratio bandwidth of 270 MHz) and high efficiency (ranging from 44 to 74%). [ABSTRACT FROM AUTHOR]

A compact triple‐band ground radiation antenna for GPS, WiFi 2.4 and 5 GHz band operations in mobile terminals is proposed. Within a considerably small area of 12 × 6 mm, by employing the inductive excitation concept of characteristic radiation modes on a mobile terminal chassis, impedance bandwidths of 21, 210, and 1820 MHz are achieved, covering the GPS, WiFi 2.4 and 5 GHz bands, respectively, at VSWR <2. [ABSTRACT FROM AUTHOR]

Two ground radiation antennas with polarisation diversity performance were proposed for MIMO WLAN applications in wearable devices. The antennas can simultaneously excite the vertical mode and horizontal mode of the ground plane and the phase difference between the two modes can be controlled by utilising an inductor‐loaded metal strip in the ground plane, generating circular polarisation. A 3:1 VSWR bandwidth of 140 MHz with high isolation (above 17 dB) and a 3 dB axial ratio bandwidth of 100 MHz was obtained. The opposite rotations generated by the two antennas resulted in good diversity performance, which was verified by the measured envelope correlation coefficient. [ABSTRACT FROM AUTHOR]