Mobile antenna performance improvement by ground mode tuning using a closed loop

IET Microwaves, Antennas & Propagation

2019

Self Cite

This research proposes a single‐fed circularly polarised (CP) antenna operating at 2.4 GHz for wireless local area network applications by utilising ground radiation, which is particularly applicable to small‐size printed circuit boards (PCBs) such as the Internet of Things (IoT) devices. To simultaneously excite two orthogonal degenerate ground modes for CP wave radiation, ground mode tuning (GMT) technique is further adopted to adjust the resonant frequencies of the two ground modes. The proposed small antenna element is located at an optimum position of the PCB based on the analysis of the theory of characteristic modes for simultaneously exciting two ground characteristic modes. Experiments verify good performances with the compact size of 0.28 λ0 × 0.28 λ0 × 0.008 λ0 (including the ground plane and antenna element) at 2.45 GHz. The proposed antenna achieves 3 dB axial ratio bandwidth of 10.6% (2.36–2.62 GHz) and −6 dB impedance bandwidth of 7.4% (2.34–2.52 GHz). The measured efficiency of the proposed antenna is 55.3%, and the direction of the maximum radiation for LHCP and RHCP is + z and – z, respectively. The measured gain is 1 dBi at 2.45 GHz. The proposed antenna applies to small‐size PCBs for CP communication, which is desirable for practical wireless products.

Section: Introductionmentioning

confidence: 99%

Compact circularly polarised antenna utilising the radiation of the ground plane based on the theory of characteristic modes

Park

IET Microwaves, Antennas & Propagation

2019

Self Cite

Micro & Optical Tech Letters

“…The bandwidth and radiation efficiency of the antenna can be improved by installing ground mode tuning (GMT) structures at the edges of the ground plane . Moreover, an additional loop‐type structure can be etched in the ground plane for the enhancement of the antenna performance . However, the additional GMT or loop‐type structures hinder the compactness of a mobile device.…”

Section: Introductionmentioning

confidence: 99%

“…[23][24][25] Moreover, an additional loop-type structure can be etched in the ground plane for the enhancement of the antenna performance. 26 However, the additional GMT or loop-type structures hinder the compactness of a mobile device. Maximizing the bandwidth (exceeding 1 GHz) and radiation performance of the GradiAnt without additional GMT structure for USB dongle applications still demand more research.…”

Section: Introductionmentioning

confidence: 99%

A wideband loop‐type ground radiation antenna using ground mode tuning and optimum impedance level

Hassan

Zahid

Khan

et al. 2019

In this article, a wideband loop‐type ground radiation antenna is proposed for USB dongle applications. Wide bandwidth has been achieved using the orientation of the antenna embedded in the ground plane along with the impedance level of the feed structure. The ground clearance of the antenna is utilized so that the ground mode is tuned to the mid‐band frequency. The impedance level is controlled by using a series combination of a lumped inductor and a capacitor in the feed loop of the antenna. A good agreement between measured and simulated results has been observed. The measured bandwidth and peak total efficiency of the antenna are 1180 MHz and 88.27%, respectively.

“…However, for wearable technology, one of the most promising applications for the IoT, compact devices must be used to ensure portability, but it is difficult to achieve high radiation performance in small devices . A great deal of research has been conducted to improve the antenna performance in compact devices by tuning the ground mode resonance that is close to the antenna resonance frequency so as to enhance the coupling between the ground plane and the antenna Most of the previous studies having this goal, including those referenced above, have focused on improving the antenna performance under ideal conditions that consider only the printed circuit board (PCB) ground and not the complicated neighboring structures. In actual devices, there are many neighboring structures connected to the ground plane that inevitably change its electrical characteristics; these structures include the cable line, battery, and speaker.…”

Section: Introductionmentioning

confidence: 99%

Performance enhancement of mobile antenna by ground decomposition

Shin

Micro & Optical Tech Letters

et al. 2018

Self Cite

We propose a ground decomposition method (GDM) to improve the performance of mobile antennas. In the GDM, overall ground impedance is analyzed as the combination of independent decomposed ground parts. In a proposed design, the overall ground mode resonance is tuned by adjusting the impedance of a flexible printed circuit board, which is decomposed according to GDM. This greatly improves the radiation performance, as verified through simulation and measurement. This proposed method is effective for mobile antenna design, and especially for actual devices that have very complicated ground configurations.