Planar inverted-F Antenna Research Articles

Dual-Band Decoupling for Two Back-to-Back PIFAs

In this communication, two dual-band back-to-back planar inverted-F antennas (PIFAs) are presented for wireless local area network (WLAN) applications. By simply etching a slot on the PIFA, the PIFA can simultaneously radiate at the WLAN 2.4 GHz (2.4–2.484 GHz) and WLAN 5 GHz (5.15–5.835 GHz) bands. To reduce the mutual coupling at the two independent bands in a guided way, long and short slots are successively engraved on the ground. The detailed decoupling process is given and discussed. The antenna was fabricated and measured. The measured results show that the two PIFAs cover the 2.4 and 5 GHz WLAN bands and the isolation can be improved to higher than 20 dB at the two independent bands.

Wing Conformal Load-Bearing Endfire Phased Array Antenna Skin Technology

In this article, a phased array antenna skin is proposed for conformally assembling scenarios and wide scanning applications. Planar inverted F antenna (PIFA) is used as a radiation element of the proposed array due to its low profile and omnidirectional radiation pattern. The PIFA element is conformally assembled in a wing of an aircraft and is designed and fabricated with the technology of composite material, which makes the PIFA element load bearing. The endfire beam synthesis is also investigated, and the proposed array supports wide-angle beam scanning in both forward and backward regions. An array of 240 PIFA elements are designed, simulated, fabricated, and experimentally tested. The fabricated sample is able to bear an overload of 1 g in the mechanical test, and all the electronic experiment results agree well with the simulation data.

Design and Fabrication of a Plastic-Free Antenna on a Sustainable Chitosan Substrate

The majority of wearable and flexible 5G and 6G devices are based on plastic substrates, that are harmful to the environment. Therefore, the development of sustainable and plastic-free radio frequency (RF) devices becomes a crucial issue. In this regard, we present a fully biocompatible Planar Inverted-F Antenna (PIFA), fabricated on a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$55 ~\mu \text{m}$ </tex-math></inline-formula> -thick chitosan substrate. Chitosan has a relative dielectric constant of 5. This antenna is working at 4.5 GHz in the sub-6 GHz band of the 5G spectrum. It has a very compact footprint of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$14\times23$ </tex-math></inline-formula> mm2 and a Specific Absorption Rate (SAR) of 0.41 W/kg. The prototype has been fabricated using an innovative fabrication protocol. A very good agreement between numerical and experimental results has been obtained. The measured realized gain is equal to 1 dBi at the resonant frequency. Our results demonstrate the suitability of chitosan as a dielectric substrate for the fabrication of plastic-free antennas and paves the way for the development of sustainable wearable devices for the Internet of Healthcare Things (IoHT) applications.

Bandwidth Maintenance and Decoupling for Two Planar Inverted-F Antennas Using Bridge Line

In this paper, a simple method is proposed that allows two planar inverted-F antennas (PIFAs) maintain their bandwidth while simultaneously reducing the mutual coupling between them. By creating a slit on each PIFA patch and then connecting the two PIFAs by a bridge line (BL), the bandwidth can be maintained and the mutual coupling between them can be simultaneously reduced to less than －10 dB. Therefore, total antenna efficiency can be significantly improved over a wide band. The proposed model is fabricated and measured, and the simulation results are validated by the measurement results.

Reduced-size Biocompatible Implantable Planar Inverted F- Antenna

The existence of implantable antennas presents intrinsic challenges as the performance of the antenna degrades due to the high losses of body tissues. In this study, a reduced-size Planar Inverted F- Antenna (PIFA) operating at Industrial, Scientific Medical (ISM) band (2.4 GHz) is designed and optimized. The design of PIFA is modeled to study and analyze the effect on the implantable antenna by placing it within the human body model, particularly in the arm. Copper is used as the patch material and the ground layer of the proposed antenna with Rogers RO3210 as its substrates. The simulation was carried within the human fat layer which is sandwich between the skin dan muscle layer. The design optimization of the antenna for operation in a human fat layer with optimal performance was achieved by reducing the size of the antenna. The antenna exhibits good stability with the reflection coefficient, S11 ≤ -10 dB at 2.4 GHz suitable for WBAN application in the environment of the human fat layer for near field communication. Analysis performance of the antenna was conducted by the transient movement of the antenna position due to the antenna being prone to movement when it is implanted within the body. The transient movement analysis is done when the implantable antenna is moving toward the skin layer and toward the muscle layer from the initial position within the fat layer. Additionally, 1 mm, 2 mm, interface of the layer and when the antenna within another tissue layer has been set to examine the performance of the implantable antenna. Correspondingly, simulation results indicate the impact of the human body layer due to the electrical properties of the human body in terms of conductivities, permittivity, and thicknesses of the layers. This has shown the design optimization of the antenna satisfies all requirements for an implantable antenna, such as small size of 5.08 × 4.00 × 0.66 (), biocompatible, low reflection coefficient of -42 dB at 2.4 GHz, realized gain of -18 dBi suitable for near field communication, and acceptable performance in fat layer. Future work will expand on conducting Specific Absorption Rate (SAR) to study the high attenuation of the radiated power of the human body on implanted antennas for the safety reason to bring in real life where it is being performed and examined.

Digitally Printed Liquid Metal Composite Antenna for Energy Harvesting: Toward Energy‐Autonomous Battery‐Free Wearable Bioelectronics

AbstractRapid progress on wearable bioelectronics holds the promise for remote patient monitoring. However, there are concerns related with the use of batteries, including the need for frequent charging, user safety, and environmental pollution. The development of rapidly deployable battery‐free patches that harvest their energy from external sources is highly desired. Here, untethered battery‐free patches through far‐field energy harvesting are demonstrated. Taking advantage of a stretchable biphasic liquid metal‐based ink and digital fabrication techniques, that is, direct printing, and laser patterning, tailor‐made customized antennas are fabricated over various substrates, including polydimethylsiloxane, Kapton, and wound‐dressing medical‐grade adhesives. Folded dipole and planar inverted‐F antennas (PIFA) are evaluated and they are optimized for an over‐the‐body scenario. Compared to previous works that only show communication of data at &lt;1 Hz, here, battery‐free acquisition and transmission of electrocardiogram (ECG) data at 100 Hz via Bluetooth is demonstrated. It is shown that using 3 parallel PIFA antennas, it is possible to harvest ≈10 mW at 30 cm from the transmitter, which is ≈7× the required power by the ECG circuit. This study proves the feasibility of next generation of battery‐free wearable biomonitoring patches/e‐textiles and demonstrates materials and methods for fabrication of optimized printed antennas.

Design and Simulation of Planar Inverted F Antenna (PIFA) for Long Term Evolution Systems

In this paper, a new calculator form is designed to calculate fundamental parameters for Planar Inverted F Antenna (PIFA). The special algorithm is configured by MATLAB R2015a software (version 8.5) in the form of a GUIDE programming language to estimate the value of antenna length (La) and width (Wa) by professional software Computer simulation technology (CST) microwave studio (Version 2019)is used to design and study the effects of each parameter in the antenna performance. The designed model was used directly in manufacturing through this method without any optimization or improvement. This antenna fabricated on the FR4 substrate has relative permittivity of 4.3 with a volume of (120601.5)mm3and the proposed antenna is fed by microstrip feeding structure. Simulation results of the (PIFA) show that the return loss, bandwidth, VSWR, and impedance are −52.100dB, 686 MHz, 1.0002and 49.99 Ω respectively at resonant frequency 3.5 GHZ.

Decoupling Between Two Back-to-Back PIFAs With Continuous Frequency Bands

This letter presents a planar inverted-F antenna (PIFAs) system for Wireless Fidelity 6 (Wi-Fi 6) and Wi-Fi 6E applications with compact size and high isolation. To realize decoupling in a guided way, single-mode structure is proposed based on common mode and differential mode theory. For the demonstration, the mutual coupling between two back-to-back asymmetric PIFAs was reduced by etching two slots on the ground. The measured results show that the two PIFAs, respectively, achieve the impedance bandwidth of 5.14–6.03 GHz and 5.90–7.24 GHz, and the port isolation higher than 17.4 dB across 5.14–7.24 GHz frequency band.

Design of Inverted F-Shape Antenna at 2.35 GHz for S-Band Applications

In this work, a simulation model of planar inverted F antenna (PIFA) will be presented with the radiating plate that has been connected to ground plane that has been accompanied by shortening plate and the FR4 substrate between ground plane and radiating plate. Where PIFA was built using computer simulation technology (CST) for the studio microwave (2019 release). The simulation model has been studied for return loss (S-parameter), bandwidth (BW), voltage standing wave ratio (VSWR), and input impedance (Zin) which are −21.875406dB, 301MHz, 1.1752855, and 50, respectively. The simulation results showed that the PIFA component covers a wide frequency band ranging between 2.202 and 2.504GHz, which can be used in Bluetooth, Wi-Fi, and Long Term Evolution (LTE) applications that are used in the fourth generation cellulares communications.

Related Reviews: Multiband Planar Inverted Antenna for Mobile Communication

Research in the field of planar inverted antennas with multiband frequencies is currently being developed. Due to the hugely increased number of mobile users, at least every time a new generation is released, a mobile communication system is released with additional features. All additional features of a mobile communication system require an antenna that resonates over a specific frequency spectrum range, meaning multiple antennas are required in a single mobile device to function across all generations for all frequency spectrums. To reduce the number of antennas on a mobile communication system device, it is necessary to design a new type of antenna that operates in a different frequency range. The inverted planar multiband antenna is designed to have changing sizes, shapes, and material properties. Types of inverted planar antennas include planar inverted-L antennas (PILA) and planar inverted-F antennas (PIFA). After analysis, the antenna designed by Juan Zhang et al. is the best solution for mobile communication systems. The designed antenna has compact antenna dimensions and four frequency bands that can be applied to N1/N78/N79 5G and 5.8 GHz WLAN. The antenna has a high gain of almost 5dB in the 5.60–7.00 GHz frequency range. They also claim that the antenna has a beam efficiency of four very high-frequency antenna points and a small side lobe that appears only at the top at the highest frequency point. But unfortunately, the antenna cannot cover the entire frequency range that must exist in a mobile communication system

A compact radio frequency identification tag antenna with loaded coupling rings for two‐side anti‐metal design

A compact ultra-high frequency radio frequency identification tag antenna loaded with a pair of rectangular coupling rings for two-side anti-metal performance is proposed. It evolves from a planar inverted-F antenna and has the same upper and lower structures. A pair of coupling rings is symmetrically loaded on the inner sides of the upper and lower substrates, and the tag's maximum power transmission coefficient can be achieved when either side of the antenna is placed on a metallic plate. The proposed tag antenna maintains a compact size of 34 mm × 28 mm × 5 mm. The measured results show that it has the lowest sensitivity of −14.8 dBm when the lower side is on a metallic plate and the lowest sensitivity of −14.2 dBm when the upper side is on a metallic plate. The proposed tag antenna is featured in a compact size, low sensitivities, and anti-metal performance on two sides. It may be used in the areas such as the industrial internet of things.

Design of a Novel Compact MICS Band PIFA Antenna for Implantable Biotelemetry Applications

An implantable stacked planar inverted-F antenna (PIFA) for biotelemetric communication in the 402-405 MHz Medical Implant Communications Service (MICS) frequency band is designed and fabricated. With the proposed PIFA structure, a slot on each radiating patch was embedded, resulting in a size reduction of 0.013 λ and a compact size of 10 × 10 × 1.905 mm3. Both in vitro and in vivo experiments verified the simulation performance with characteristics of -10 dB bandwidth of 29 MHz, radiation efficiency of 0.9%, and a maximum far-field gain of -18.8 dB. We calculated the safety power delivered to the antenna using the specific absorption rate (SAR) limitation standard. Compared to other implantable antennas for biotelemetry, this antenna performs comparably and has a smaller size. This design would further develop implantable medical devices that communicate in the MICS band.

AN EMPIRICAL APPROACH TO DESIGN A PIFA ANTENNA

Abstract: A parametric study is performed on a Planar Inverted F Antenna (PIFA) that operates at the frequency of 900 MHz The effect of the variation of the parameters on the bandwidth (BW) is analyzed. The study is performed using the Finite Element Method (FEM) numerical technique and the High Frequency Structural Simulator (HFSS) software.Regression analysis is applied on the data obtained from the simulation to present a mathematical model that estimates the fractional bandwidth FBW. An empirical equation that predicts the FBW of the PIFA is introduced. The equation uses the effective designparameters; substrate material thickness and ground plane dimensions as predictors. A comparison between the results calculated by the equation and the results obtained via simulation is carried out for validation purposes. The results are found to be very close except for the values corresponding to substrate thicknesses above 6mm. Moreover, a second simulator using a different numerical technique is used for further verification.A PIFA that operates at the 900 MHz frequency is fabricated. The results obtained from the physical measurement are compared with the results calculated by the empirical equation and the results obtained from the simulation. Close compatibility is observed.

A Shared-Aperture Antenna for (3.5, 28) GHz Terminals With End-Fire and Broadside Steerable Beams in Millimeter Wave Band

In this paper, a concept of partial structure reuse is presented and on this basis a 3.5/28 GHz shared-aperture antenna supporting two-dimensional (end-fire and broadside) steerable beams in MMW band is developed. The antenna consists of a 3.5 GHz planar inverted-F antenna (PIFA) and two 1&#x00D7;6 28 GHz substrate integrated DRA (SIDRA) beam-steerable arrays, in which partial structures of the PIFA are reused by the two MMW arrays. To improve the performance of PIFA, two narrow slots and one lumped capacitor are introduced to reduce its H-plane cross-polarization and enhance the operating bandwidth, respectively. To verify the design, antenna prototypes were fabricated and measured. Measured results show that the antenna can cover a dual-band of 3.28-3.67 GHz (11.2%), 26-29.7 GHz (13.2%) for end-fire and 25.9-29.7 GHz (13.8%) for broadside. The peak gains of 4.8 dBi, 10 dBi (end-fire) and 10.8 dBi (broadside) are obtained by the MW element and two 1&#x00D7;4 MMW arrays, respectively. Each of the MMW arrays can steer the beams from -50&#x00B0; to +50&#x00B0;, covering different parts of the space. The shared-aperture antenna has a compact size of 0.45&#x00D7;0.3&#x00D7;0.03 &#x03BB;01 3 (&#x03BB;01 is the free-space wavelength at 3.5 GHz), making it suitable for terminal applications.

A Compact Broadband Planar Inverted-F Antenna with Dual-Resonant Modes

In this paper, a compact broadband planar inverted-F antenna (PIFA) with dual-resonant modes (TM1/2,2 and TM3/2,0) is proposed for 5G applications. By loading a pair of horizontal slots on the patch, the TM3/2,0 mode can be shifted downward and combined with the TM1/2,2 mode, leading to a dual-mode operation. Meanwhile, another pair of slots, which are orthogonal to the previous pair, is introduced to improve the impedance matching of the antenna. Moreover, the substrate with a high dielectric constant is used in this design to achieve a compact antenna size. In order to verify the principle and the design method, an antenna prototype was fabricated and measured. Experimental results show that the PIFA has a good performance with a −10 dB impedance bandwidth of 14.5% (3.17–3.67 GHz), a peak gain of 6.23 dBi, a low cross-polarization level of −17.3 dB, and a compact size of 0.45 × 0.26 × 0.03 λ013 (λ01 is the free-space wavelength at 3.5 GHz). The antenna is predicted to be suitable for 5G terminal applications.

A Pattern Correlation Decomposition Method for Analysis of ESPAR in Single-RF MIMO Systems

A systematic and general method for obtaining orthogonal far-field radiation patterns using any electronically steerable parasitic array radiator (ESPAR) embedded in a propagation environment with an arbitrary power angular spectrum (PAS) is described. The method is useful in designing single-RF multiple-input multiple-output (MIMO) systems where the orthogonal patterns can be utilized as a basis set for beamspace MIMO. The method utilizes the correlation matrix of the open-circuit radiation patterns and is termed the pattern correlation decomposition method (PCDM). PCDM is applicable to any antenna type (including realistic antennas with losses), array configuration, PAS and overcomes the limitations of previously proposed techniques. PCDM also provides closed-form solutions for the antenna currents to generate the orthogonal patterns. It also provides an estimate of the effective aerial degrees-of-freedom of the ESPAR. In addition, efficient optimization approaches to finding the optimal reactive loads that excite the required orthogonal radiation patterns are provided. Simulation examples using a 5-element and a 8-element planar inverted-F antenna array including material losses in various PAS are provided. These show that the proposed approach increases system capacity by up to 7 bits/s/Hz or equivalently reduces the required transmit power by up to 73% compared with previous approaches.

A Compact Four Elements PIFA Array for RFID Reader Applications

In this paper, a novel compact 2×2 Planar Inverted-F Antenna (PIFA) array with four elements is proposed. This antenna array operates in Industrial, Scientific, and Medical (ISM) band for Radio Frequency Identification (RFID) reader applications, and it consists of four identical PIFAs radiating elements placed on the top of the upper substrate, two substrates, and a proposed feeding network placed on the bottom of the lower substrate. The PIFAs radiating elements are placed at the edges of the ground plane to reduce mutual coupling between them. The total size of the antenna array is only 62×45×8.6 mm3. The substrate used is FR4 with constant dielectric relativity of 4.4, a thickness of 0.035 mm, and a height of 1.6 mm. The proposed antenna is simulated and optimized using Computer Simulation Technology Microwave Studio (CST MWS) software. Simulation results show that the PIFA array offers good characteristics in terms of reflection coefficient, isolation (decoupling), and radiation patterns which makes it a good candidate for ISM band applications.

A Double-Layer Patch Antenna for 5-6 GHz Wireless Communication.

This paper proposes a compact double-layer microstrip patch antenna with a wide bandwidth of 4.83–6.1 GHz and a gain reaching 4.7 dBi. By folding its mirror image through the electric field symmetry principle of the microstrip antenna, its electrical properties are maintained, and the physical size is halved to the compact size of only 25 × 40 mm2. The proposed antenna has the radiation characteristics of a planar inverted-F antenna (PIFA), which can generate the first resonant frequency and realize omnidirectional radiation characteristics. By coupling and feeding the upper patch, the second resonant frequency of the proposed antenna is produced and the directional radiation characteristics of the microstrip patch antenna can be achieved. The consistency of the results between the simulation and test indicates that the proposed antenna design is an ideal potential choice for home wireless local area network (WLAN) communication.

An On-Chip Planar Inverted-F Antenna at 38 GHz for 5G Communication Applications

This paper presents an on-chip planar inverted-F antenna (PIFA) implemented in TSMC 180 nm CMOS process technology. The antenna operates at a 5 G millimeter-wave center frequency of 38 GHz. The ultrathick metal (UTM) layer of the technology is utilized to implement the on-chip antenna (OCA). The OCA is positioned close to the edge of the microchip for improving the gain performance of the antenna. The open end of the antenna is folded to develop a top-loaded PIFA structure yielding better 50 Ω impedance matching and wider bandwidth. On-wafer measurements are conducted through the Cascade Microtech Summit 11K probe-station and ZVA-50 vector network analyzer to measure the return loss and gain of the fabricated on-chip antenna. The measurements are performed after placing the fabricated OCA over a 3D-printed plastic slab to minimize the reflections from the metallic chuck of the probe station. The measurement results show that the fabricated on-chip PIFA achieves a minimum return loss of 14.8 dB and a gain of 0.7 dBi at the center frequency of 38 GHz. To the best of the authors’ knowledge, the presented OCA is the first on-chip PIFA designed, fabricated, and tested at the 5G millimeter-wave frequency of 38 GHz.

Dual Antenna Coupling Manipulation for Low SAR Smartphone Terminals in Talk Position

A rigorous analysis of the concept of coupling manipulation utilizing two antennas suited to modern smartphone devices in talk position for voice calls is presented. By using the optimum relative phase between the elements, they can substantially reduce the specific absorption rate (SAR) but still maintain efficiency due to the splitting of power between them and by exploiting a suitable level of interelement coupling. The same antenna elements can still be used for multiple-input–multiple-output (MIMO) when not in talk position without heavily degrading their fundamental capacity limit, but this is of secondary importance. The concept could be applied to frequency ranges used in mobile communications from 1.8 to 6 GHz where the ground plane has sufficient form factor. Extensive simulations using two planar inverted-F antennas (PIFAs) operating at 2.4 GHz are carried out to demonstrate conceptually how two antennas can be optimized to reduce SAR by over 50% compared to a single antenna element. SAR reduction is maintained regardless of the user’s head composition and how they are handling the device in a talk position. Antenna prototypes are measured and compared to verify the capacity when the handset is used away from the body with two MIMO terminal antennas.