Compact Low-profile Antenna Research Articles

Wearable Antennas for Virtual Reality Cross-Body Links

Cross-body link refers to the wireless connection between two wearable devices when they are both worn or near the body, such as that of a virtual reality (VR) headset and its controllers. It is one of the most challenging wireless scenarios in terms of link budget, due to severe shadowing effects when controllers are placed at the back side of the body. This is especially true when the users are in an outdoor environment where there is less reflection from the surrounding. This paper investigates the wireless propagation mechanism, including line-of-sight, ground reflection, and creeping waves. Based on that, through simulation and measurement experiments, this work analyzes the impact of different antenna designs on the cross-body link of VR/AR devices, including one novel compact low-profile antenna named Distributed Monopole (DM), and two conventional antennas. Due to the polarization advantages, both the novel DM antenna and the patch antenna shows significantly better performance than the dipole antenna. The DM antenna also shows a 2-4 dB advantage over the patch antenna due to its omni-directional field pattern. Time-domain analysis and statistical approaches are suggested to fully characterize the cross-body link of VR/AR antennas and body propagation.

Design of Feeding Techniques for Slotted Rectangular Microstrip Patch Antenna (RSMA)

Microstrip Patch Antenna is a compact low profile antenna which can be embed on the surface. This paper explains various feeding techniques applicable for rectangular microstrip antenna for 3.4 to 3.6 GHz for WiMax applications. Based on contact and non-contact techniques various feeding methods are discussed here. RF power is feed directly to the patch using conducting element for contact feed where as in non-contact feed the power is feed to the patch and the microstrip line through electromagnetic coupling. The simulation results shows the comparative study of various performance metrics such as Return Loss, Radiation Pattern in 2D and 3D, VSWR, Field Directivity, Total Power Efficiency, Current Distribution and Total Field gain using IE3D EM software.

Low-Profile Compact Antenna for Octa-Band Metal-Rimmed Mobile Phone Applications

In this article, a compact low-profile antenna for octa-band unbroken metal-rimmed smartphone applications is proposed. The antenna consists of a capacitive coupling rectangular vertical plate and two new-type extended ground branches. For lower frequency, the LTE700, GSM850, and GSM900 bands are provided by the bezel mode which is generated through capacitive coupling excitation of a rectangular vertical plate to the bezel. For upper frequency, the DCS, PCS, UMTS, LTE2300 and LTE2500 bands are covered by the multiple modes of two ground branches. With the proposed structure, the operating bands can be expanded and optimized simply. All the mentioned bands are achieved in the size of ( $70 \times 7 + 20 \times 2$ ) $\times $ (1.5 + 0.8) mm3 on the 130 mm $\times \,\, 70$ mm system board. The antenna is fabricated and measured to verify this proposal. The tested results include reflection coefficient, radiation patterns, efficiency, and gain.

Design of a compact dense dielectric patch antenna based on half‐cut technique

In this article, a half-cut rectangular dense dielectric patch (DDP) with one grounded side plane is theoretically investigated for designing a compact low-profile antenna. According to the properties and the E-field distribution of the dominant TM101 mode, the half-wavelength (λ/2) DDP can be bisected by effectively shorting the center plane to the ground, resulting in a miniaturized half-cut λ/4 DDP. The size of the DDP is effectively reduced by 50% while maintaining the original resonant frequency of the dominant TM101 mode. The half-cut λ/4 DDP can be well excited through aperture coupling for antenna design. The design procedure of the proposed antenna is given in detail. For demonstration, an antenna prototype centered at 4.15 GHz is implemented and measured. The simulated and measured results are given, showing good agreement.

Design and performance analysis of dual-band wearable compact low-profile antenna for body-centric wireless communications

AbstractIn this paper, we present a novel dual-band wearable compact flexible antenna for body-centric wireless communications (BCWCs). The design is based on a modified planar dipole with parasitic elements, meandered lines, and a rectangular reflector embedded into a hydrophobic rubber-textile multilayer substrate in order to get both good antenna performance and mechanical properties. The antenna's structure is analyzed and optimized in free space (FS), on a numerical and an experimental homogeneous flat phantom. The overall dimensions of the antenna are 50 mm × 40 mm × 4.6 mm and a prototype mass of 11 g, which makes it suitable for practical applications in BCWCs. The built prototype resonated at 2.47 GHz with a |S11|−26.90 dB and at 5.42 GHz with a |S11|−24.60 dB in the FS. The measured bandwidths are 500 MHz (2.2–2.7 GHz) and 1000 MHz (4.65–5.75 GHz) at lower and higher bands, respectively. The antenna exhibits a measured maximum gain of 1.17 dBi at 2.66 GHz and a radiation efficiency of 28.44% in FS. The 10 g average maximum specific absorption rate is 0.165 W/kg at 2.70 GHz and 0.520 W/kg at 5.24 GHz when the antenna is placed on the numerical phantom at net input power 0.1 W.

KU-BAND SUSPENDED MESHED PATCH ANTENNA INTEGRATED WITH SOLAR CELLS FOR REMOTE AREA APPLICATIONS

A new structure design of a dual-band suspended microstrip meshed patch antenna integrated with a polycrystalline silicon solar cell for Ku-band satellite applications is proposed and presented. This antenna element is a basic building block for a Ku-band meshed array antenna used for two-way satellite internet and TV applications at rural and remote locations. The antenna covers the operating frequency range from 11.7GHz to 12.22 GHz downlink band and from 14.0GHz to 14.5GHz uplink band allocated by the ITU to the Regions 1 and 2. While achieving 500MHz bandwidth across each band, fully covering the Ku-band uplink and downlink frequency bands, the antenna offers a single element gain of 6.05 dBi in the downlink band and 7.61 dBi in the uplink band. The antenna has been fabricated and measured, and good agreement is achieved between the experimental and simulated results. In addition, a good compromise between RF performance and optical transparency is obtained. The overall visible light transmission is found to be approximately 87%. A compact low-profile antenna element is also achieved.

Wide-angle scanning planar array with quasi-hemispherical-pattern elements

A compact quasi-hemispherical-pattern antenna, two linear wide-angle scanning arrays, and a planar wide-angle scanning array are proposed. To increase the field-of-view scanning range of arrays, a compact low-profile antenna with a quasi-hemispherical pattern is introduced firstly. When the ground is infinite, the proposed antenna has a quasi-hemispherical pattern, i.e., an approximately uniform radiation in the upper half space. Afterward, two linear arrays arranged along the length and width of the proposed antenna’s radiation patch are presented. The main beams of the two arrays with 16 active elements can scan from less than −75° to more than +75°. When the linear array element number is 128, the maximum scanning angle can reach 86°. At last, a planar array with 16 × 16 active elements is proposed. In two special planes, xz plane and yz plane, the main beams of the planar array can scan from less than −77° to more than +77° with a gain fluctuation less than 5 dB and a maximum side lobe level (SLL) less than −10 dB. An excellent wide-angle-scanning performance both in linear and planar arrays can be obtained using the proposed method.

인체 표면 통신을 위한 TM31고차 모드 반원-링 인체 부착형 마이크로스트립 패치 안테나 설계

본 논문에서는 모노폴과 같은 방사특성을 갖고 인체 표면 간 통신을 위한 <TEX>$TM_{31}$</TEX> 고차 모드 반원-링 마이크로스트립 패치 안테나를 제안하였다. 제안된 안테나는 단락 핀을 이용하여 <TEX>$TM_{31}$</TEX> 고차 공진 모드를 형성하였고, 평면형임에도 불구하고 모노폴과 같은 방사특성을 갖는다. 패치안테나의 좁은 대역폭을 확장하기 위해 <TEX>$TM_{31}$</TEX> 모드 C-형 반링 패치를 반원 패치에 인접시켰으며, 소형화를 위해 half mode를 사용하였다. 인체 착용환경을 고려하여 마이크로스트립 라인을 이용하여 급전하였다. 제안된 안테나는 ISM(Industrial, Scientific, and Medical) 2.45 GHz 대역(2.4~2.485 GHz)에서 <TEX>$0.25{\lambda}_0{\times}0.46{\lambda}_0{\times}0.025{\lambda}_0$</TEX>의 크기를 갖고, 2.38~2.49 GHz에서 4.24 %의 10-dB 반사손실 대역폭을 갖는다. 인체의 영향을 고려하기 위해 2/3 근육-등가 반고체형 모의인체를 제작하고, 이를 이용하여 안테나에 미치는 인체의 영향을 분석, 검증하였다. 또한, 실제 인체 상황에서 제안된 안테나를 통해 인체 표면 간 링크의 통신 성능 분석을 위한 실험을 수행하였다. In this paper, a <TEX>$TM_{31}$</TEX> higher order mode half circular-ring microstrip antenna with monopole-like radiation characteristic for on-body communication is proposed. By using shorting vias, <TEX>$TM_{31}$</TEX> resonance mode was excited, while achieving compact low-profile antenna with monopole-like radiation characteristics. To overcome the narrow bandwidth of a patch antenna, a C-shape half ring patch with shorting vias having <TEX>$TM_{31}$</TEX> mode is closely located around a half circular patch. For size reduction, half mode is adopted. The proposed antenna has the overall dimensions of <TEX>$0.25{\lambda}_0{\times}0.46{\lambda}_0{\times}0.025{\lambda}_0$</TEX> at the industrial, scientific, and medical(ISM) 2.45 GHz band(2.4~2.485 GHz) and the 10-dB return loss is 4.24 % ranging from 2.38 to 2.49 GHz. To verify body effect, two-thirds muscle equivalent semi solid phantom was fabricated and used to measure the antenna performance. A communication link is analysed to investigate the effect of human-body movements and antenna locations.