Flexible Liquid Metal Alloy (EGaIn) Microstrip Patch Antenna

A precise layer alignment is crucial to ensure performance repeatability of multilayer microstrip antennas. We introduce a novel lab-scale construction process for multilayer microstrip textile patch antennas that consists in combining an alignment method, based on laser-cut wood frames to perform accurate layer alignment, with a fast intralayer attachment method, based on thermally activated adhesive sheets. This lab-scale construction process is validated with an electromagnetically coupled microstrip rectangular patch textile antenna operating in the 2.45 GHz ISM band. It has been reproduced eight times to validate the proposed construction process. The differences between desired simulated versus measured average values of the resonant frequencies, impedance bandwidths, gains, and total efficiencies equal 6.25 MHz, 21.5 MHz, 0.6 dBi, and 4.45%, respectively. Moreover, the standard deviations of measured resonant frequencies, impedance bandwidths, gains, and total efficiencies equal 24.54 MHz, 14.02 MHz, 0.15 dBi, and 3.57%, respectively. These results confirm that the novel lab-scale construction process provides good performance repeatability of multilayer microstrip textile patch antennas.

This research investigates a monopole patch antenna for Wi-Fi applications at 2.45 and 5.2 GHz, and WiMax at 3.5 GHz. A low-cost and flexible graphite sheet with good conductivity, base on graphite conductive powder and glue is used to create a radiator patch and ground plane. Instead of commercially available conductive inks or graphite sheets, we use our self-produced graphite liquid to create the graphite sheet because it is easy to produce and inexpensive. The antenna structure is formed using a low-cost and easy hand-screen printing approach that involved placing graphite liquid on a bendable polyester substrate. This research focuses on designing and developing a low-cost, thin, light, and flexible patch antenna for wireless communication and smart glass applications. The proposed antenna utilizes CST microwave software for simulations to improve the parameters before fabrication and measurement. The simulation and measurement results for the reflection coefficients at 2.45 GHz, 3.5 GHz, and 5.20 GHz are reliable and cover the required resonance frequencies, antennas gain are 1.91, 1.98, and 1.87 dB, respectively. Additionally, the radiation patterns of both results are omnidirectional. In the experiments, bending the proposed patch antenna along with the cylinder with the radii of 60, 40, and 25 mm yielded the same measurement results as the unbent patch antenna.

In this article, we propose a liquid‐metal‐fluidically polarization reconfigurable microstrip patch antenna. The edge‐truncated patch is designed to generate circular polarization (CP), and two microfluidic channels are designed for the polarization reconfigurability. Therefore, the polarization of the proposed antenna is switched to linear polarization (LP) from the CP when the liquid metal is injected on the microfluidic channels. The microfluidic channels are fabricated on the polydimethylsiloxane (PDMS) material, and eutectic gallium‐indium (EGaIn) is used as the liquid metal. The performance of the proposed antenna is numerically and experimentally demonstrated. The measured 10‐dB impedance bandwidth is 1.579‐1.619 GHz and 1.563‐1.587 GHz for the CP and LP modes, respectively. At the CP mode, the measured axial ratio (AR) and RHCP gain at 1.595 GHz are 2.267 dB and 6.59 dBic, respectively. At the LP mode, the measured AR and peak gain at 1.585 GHz are 12.335 dB and 5.18 dBi, respectively.

Modern wireless communication system plays a substantial role in day-to-day life. Wearable antennas are a key portion of wearable 5G communication applications, the Internet of Things (IoT), and biomedical systems. Compact efficient antennas considerably affect the performance of wearable systems. Wearable electronics and related technologies have gained tremendous traction in recent years. Several key developments contributed to increasing wireless communication's popularity, including the miniaturization of devices, the arrival of high-speed wireless networks, low-power, ultra-compact SoCs, and increasing battery performance. Various types of printed antennas are used in wearable electronics, which enable data to be sensed, retrieved, and exchanged wirelessly with a host device or an IoT gateway. The resolve of this chapter is to deliver the basic idea of flexible and wearable patch antennas and their fundamental concepts. Numerous types and methods have been deliberated in the current state-of-the-art field of the patch antenna. In this chapter, several wearable patch antennas are discussed that best suit modern-day wireless communication systems. Current challenges and limitations of the flexible and wearable patch antennas for modern wireless applications are discussed in detail with some possible suggestions.

In this proposed work a compact dual band and wideband slot loaded multilayered patch antennas are presented for WLAN and WiMAX applications. The antenna parameters such as return loss, radiation pattern, gain, frequency ratio, VSWR, efficiency, group delay and beam-width are discussed. The bandwidth of the proposed dual band antenna at lower resonant frequency is 9.53 % (simulated) and 13.2 % (experimental) whereas at upper resonance frequency is 6.95 % (simulated), and 13.32 % (experimental) while for wideband it is 26.7 % (simulated) and 25.09 % (experimental). The proposed antenna structures are simulated by HFSS tool, fabricated and the simulated results are verified by experiment.

A broadband microstrip patch antenna with multi-layer substrate for fuze application is designed. The multi-layer substrate is composed of the bottom layer of Si with low electric conductivity, the middle and the top layers of Si with high electric conductivity. An air cavity is fabricated by inductively coupled plasma (ICP) etching in the middle layer of Si to reduce the effective dielectric constant of the multi-layer substrate. The multi-layer substrate microstrip patch antenna is simulated and optimized by finite element method. The simulation results show that operating at 10GHz, the bandwidth and the gain of the multi-layer substrate microstrip patch antenna are 15.5% and 6.1dB respectively, which meet the needs of the application in fuze well.

A variational method in the spectral domain is used to determine the quasistatic capacitance of a patch antenna within a nonhomogeneous multilayer structure. The patch is modelled both by a one dimensional analysis using a segment of an infinite transmission line and by a full two-dimensional representation. A new technique is presented for determining the relative permittivity of an equivalent single-layer structure, from which the frequency-dependent effective permittivity is obtained. Results for a number of different antenna structures are given and show good agreement with measured values.

The goal of the proposed research is to construct the Phase controlled directed antenna using low-loss dielectric and high relative permittivity material for the substrate. In this paper also presented two beams antenna. First part of the paper contains the simulation of such antenna using the software, based on the Finite Element Method for the purpose to find optimal parameters of such antenna before its construction. Our goal is to find the best parameters of the antenna, using the numerical experiment, to achieve desired radiation parameters: well matching to the open space; phase controlled narrow-beam; wide-band. There was designed phase controlled and two beams patch antennas at 7.6 GHz and 7.8 GHz respectively. Phase controlled antenna was archived by cutting patch antenna by half. Two beams antenna where made by cutting patch by two parts same type cutting corners from it. For simulation it was used 6.8 relative permittivity material for the substrate.

This paper provides the design of a wideband compact flexible rectangular slotted patch antenna on polydimethylsiloxane (PDMS) and its performance analysis for wearable applications. Rectangular slots on the patch plane and partial ground are included to improve the operational bandwidth (BW) of the antenna. The proposed antenna is designed on a flexible PDMS substrate with relative permittivity of 2.74 and loss tangent of 0.057 and optimized to a small size of 35 × 25 × 2 mm3 using a powerful, 3D electromagnetic simulation software package (Computer Simulation Technology) studio suite to satisfy the needs of lower fifth generation, Worldwide Interoperability for Microwave Access, Wireless Fidelity, and Industrial, Scientific, and Medical band wireless applications. The proposed antenna with a microstrip line feed has two resonant frequencies at 3.5 GHz and 4.85 GHz and it operates over the frequency range of 2.53 GHz to 5.81 GHz. In free space, the antenna provides a large BW of 3.28 GHz, a maximum radiation efficiency of 85.25%, and acceptable return loss, Voltage Standing Wave Ratio, gain, directivity, and radiation characteristics over the operational frequency range. Under the on-body condition, the antenna’s performance analysis, bending analysis, and Specific Absorption Rate (SAR) analysis were also performed on a body phantom model, yielding positive results with SAR values less than the recommended safety limit of 1.6 W/kg. The comparative performance analysis proves the suitability of this antenna for applications in wearable electronics.

The new technology referred to as substrate integrated waveguide (SIW) is considered to be appropriate for fifth-generation (5G) networks. In the presented work, SIW antenna with two slots was developed at 28GHz for improving the antenna's parameters. The distance between vias was controlled for minimizing the antenna's losses. SIW technology was developed at higher frequency, also has compact size and good performance. Yet, SIW antennas have losses at high frequencies due to the distance between vias. The radiating patch of antenna that is being provided depending on without and with slots. For increasing the antenna's bandwidth and gain, two types of slots—zigzag and straight—were etched onto the patch. Low losses, significantly high gain and efficiency, also overall structural size of 7.11 x 14.8, both without and with slot, were attained with the suggested design. Straight slot as well as zigzag antennas that are suggested resonate at 28 GHz. The measured results have shown that the proposed antenna could provide 95% efficiency, 8.1 dB gain, also huge band-width of at least 3.1GHz at 28GHz. For boosting the antenna's primary parameters, single antenna was transformed into 1x4 array that was simulated as well as measured. SIW antenna is suitable for 5G applications base stations, according to measurement results.

In this paper, a switchable metamaterial absorber/reflector has been presented based on microfluidic technology. The proposed structure consists of a meandered pattern engraved in an elastomeric substrate, where the liquid metal alloy (eutectic gallium indium, EGaIn) can be injected through the microchannels. The novelty of the design lies in its switching response from perfect reflection to polarization-selective absorption, depending on the injection of EGaIn in the channels. The structure, with liquid metal alloy, exhibits narrow-band absorption at 5.92 GHz during vertical polarization, whereas the absorption is shifted to higher frequency range (15.09 GHz) under horizontal polarization. Surface current distribution of the geometry has been studied to explain the absorption mechanism for different polarizations. Finally, the structure has been fabricated and experimentally verified, thereby confirming the potential use of microfluidic technology based structures.

In this paper L-strip Electromagnetically coupled rectangular patch antenna is proposed and simulated results were obtained by HFSS tool. The frequency range covered by this single antenna is 1800MHZ to 2370MHZ with −10db return loss with optimal height of the patch from the ground plane 16.8mm. The antenna parameters which influence the gain, bandwidth, return loss was analyzed and graphs are plotted. The design mainly focuses on 3G internet services. It covers the DCS, PCS and UMTS. In addition, significant matching and high gain of 10.8 dB at 2.4GHz is obtained.

In this work, a flexible microstrip patch antenna has been designed to be working at 2.4 GHz using rubber as the substrate material with permittivity of 3.0 and loss tangent of 0.02. The proposed antenna has been designed to achieve a good result of reflection coefficient, vswr, gain, directivity, and antenna efficiency at the selected operating frequency. The design of rectangular microstrip flexible antenna with two-element horizontal array has depicted a positive performance for wireless frequency band specifically at 2.4 GHz. The selected design has achieved a return loss of -49.659 dB, VSWR of 1.007, gain of 8.16 dBi, directivity of 9.21 dBi and 78.5% of total antenna efficiency. The proposed design is expected to be able to complement with the wearable innovation such as technology used on human body and is applicable for basic communication applications.

Flexible inkjet-printed proximity-fed patch antennas, designed for the 24-GHz Industrial, Scientific, and Medical (ISM) band, are demonstrated in this letter for the first time featuring a multilayer inkjet deposition process. Inkjet printing of antennas allows for the low-cost, noncontact, and additive fabrication of RF components onto nearly any host substrate or package. The inkjet-printing process exhibited in this leter is the first inkjet process to demonstrate multilayer printed antennas, enabled by a new printable dielectric ink that allows for the deposition of thick dielectric layers. Printed coupled patch antennas with realized gains of over 4 dBi and four-element coupled patch arrays with gains of over 7 dBi are demonstrated on a flexible liquid crystal polymer (LCP) substrate. The antenna gain, return loss, and pattern are presented and demonstrate the repeatability and design flexibility of the novel inkjet-deposition process.

A highly flexible and conformable polymer-based patch antenna, based on commercial off-the-shelf (COTS) room temperature vulcanized silicone (RTV) silicone rubber substrate combined with a stretchable silver conductor, is presented. The measured performance of the antenna is compared with a reference antenna, which uses the same RTV silicone rubber as substrate and polyimide with copper cladding for the top layer and the ground plane. The measured gain of the polymer-based antenna is $\sim$ 4 dB lower compared to the reference antenna. This is also predicted by simulations and is due to the lower conductivity of the conductive polymer compared to copper in the reference antenna. The radiation pattern and gain of the polymer-based antenna remain mostly unaffected when the antenna is conformed to cylindrical surfaces of various radiuses.