Planar inverted-F Antenna Research Articles

A Compact Planar MIMO Inverted‐F Antenna (PIFA) for Sub‐6 GHz 5G Communication and IoT Wireless Networks Applications

ABSTRACTA compact eight‐port MIMO structure containing planar inverted‐F antennas (PIFAs) as radiating elements is designed for 5G cellular communication applications within the sub‐6 GHz band. The proposed antenna consists of four radiating elements that are placed at four corners on the same plane of geometry. The overall dimension of the ground plane is considered to be 59 mm × 120 mm to make it convenient for modern smart mobile handsets. Each radiating element has 2‐feeding plates, which are situated perpendicular to each other in orientation to make the arrangement cross‐polarized, which in turn exploits polarization diversity as well as spatial diversity among the combination of different radiating elements. The patches are structured by embedding rectangular slots in a meandered shape, and the ground plane is configured by introducing rectangular slots and narrow metallic strips. The prototype of the prescribed MIMO PIFA model has been fabricated and experimentally tested. It shows multi‐band operations (3.27–3.37, 4.16–4.35, 4.93–5.06, and 5.47–5.68 GHz) within the sub‐6 GHz spectrum. The isolation among various patches is observed within the range of −35 dB to −42 dB. The peak gain reaches around 8.1 dBi. The designed MIMO PIFA exhibits superior diversity performance by producing ECC ≤ 0.0006, DG ≈ 10 dB, CCL < 0.20 bits/Hz/s, and MEG ≤ −3 dB. Furthermore, the specific absorption rate (SAR) is evaluated according to the standard values of fat, skin, and muscle at 3.3 GHz. The prescribed model maintains acceptable SAR values for 1‐g and 10‐g tissues, which makes it suitable for smartphone applications.

Textured CoZn-18H hexaferrite with enhanced Snoek’s product and suppressed magnetic loss

Modern communications have created a great demand of magneto-dielectric functional materials having low loss and high permeability properties under the sub-6 GHz band. CoZn-18H planar hexagonal ferrites with strong magnetic anisotropy are more promising in meeting these requirements than that of traditional ferrites. The textured CoZn-18H hexagonal ferrites were synthesized by the reactive templated grain growth (RTGG) method to obtain high magnetic resonance frequency without sacrificing permeability. The layered texture composed of flaky hexagonal particles with a high aspect ratio played an important role in obtaining high permeability and high magnetic resonance frequency. The permeability μ′, magnetic loss tangent tan δμ, and performance factor (PF) of the textured CoZn-18H hexagonal ferrite with the highest Snoek’s product (SP = 6.99 GHz) under 3.41 GHz were 1.66, 0.10, and 56.61 GHz, respectively. Compared with the traditional pure dielectric substrate, a planar inverted F antenna (PIFA) working at 3.0 GHz with a miniaturization rate of 18.1 % was simulated based on the textured CoZn-18H hexagonal ferrite. These results demonstrated that the method of preparing textured CoZn-18H hexagonal ferrites without the application of a magnetic field was effective and revealed the potential of textured planar hexagonal ferrites synthesized by the RTGG method of high-frequency and low-loss applications.

Wideband patch antenna through introducing co‐plane terminal

AbstractWideband operation is a crucial topic in patch structure research. Various wideband methods have been developed for patch antennas. However, some of the key benefits of patch antennas, such as semi‐space radiation and easy fabrication, are degraded. In this study, we refer to the planar inverted‐F antenna (PIFA) and propose a co‐plane terminal loading strategy, resulting in an antenna model termed the co‐plane terminal loaded antenna (CTLA). It transforms the dipole‐to‐background metallic via in PIFA to a dipole‐to‐feed gap in CTLA. Because the gap is a coupling connection, the impedance‐match and resonant‐frequency performance improve, resulting in a wider bandwidth. Based on the proposed approach, three CTLAs, including an original CTLA, an improved CTLA, and a multi‐path CTLA, were constructed and simulated, with relative bandwidths of 63.5%, 55%, and 62%, respectively. The radiation pattern is typically patch‐like, radiating in semi‐space, and hybrid polarisation over the working band. Finally, the improved and multi‐path CTLAs are fabricated and measured to validate this method and ensure that the results are consistent with the simulation results accurately. This study proposes a terminal‐loading method for patch structures, which results in wideband radiation. It can be used in wideband phased arrays, communication systems etc.

Implementation of Wide Angle FoV Radar Module for ADAS Systems

In this study, we propose the wide field of view (FoV) radar module for autonomous vehicles. The proposed wide FoV radar (WFR) module was constructed using of an RF module comprising wide beamwidth microstrip patch antennas, an AWR1642 radar sensor chip, and a control module. To achieve a wide FoV of 150° using the fabricated radar module, the 3-dB beamwidth characteristic of the applied microstrip patch antenna had to wider than 150°. The patch antenna was designed using a comb-line structure along 10-by-1 array structure, each radiator characterized by a shorted patch structure, such as a planar inverted-F antenna. The designed antenna was then fabricated on the same board surface as the sensor chip. To identify the characteristics of the implemented radar module, a trihedral corner reflector with a radar-cross-section of 180 m2 was used as the reflector target, and the CA-CFAR (cell averaging constant false alarm rate) target detection algorithm was applied. The measurement results, showed good detection performance of the radar in the view angle of 150°, from -75° to +75°, and a broad bandwidth of 4 GHz in the 77–81 GHz millimeter band. Therefore, the proposed WFR is applicable for used in blind spot detection sensors in autonomous vehicles.

The preparation and performances of Co-Zn 18H hexagonal ferrite with an ultra-high magnetic resonance frequency and low-loss characteristics

Modern 5G communication technologies require evolution of antennas towards high frequency and miniaturization. The search for magneto-dielectric materials with simultaneous high permeability, matched dielectric constant, and low loss properties for sub-6 GHz band applications has received considerable attention from both academic and industrial circles. Due to the low magnetic resonance frequency and high magnetic loss, traditional spinel and hexagonal ferrites hardly meet these requirements. In this study, polycrystalline Co-Zn 18H ferrites (Ba5Co2-xZnxTi3Fe12O31) were synthesized by co-precipitation method with only one-step sintering process. The polycrystalline Co-Zn 18H hexagonal ferrite possesses an ultra-high natural resonance frequency (14.5 GHz) and low magnetic loss (tanδμ≤0⊡10), which provides a better performance factor (PF= 68.6 GHz) at a higher operating frequency (4.97 GHz) compared to traditional microwave ferrites. The miniaturization rate of the planar inverted F antenna (PIFA) with Co-Zn 18H ferrite working at 4.0 GHz reaches 13.3 %. These results demonstrate the high potential of Co-Zn 18H ferrites for high frequency and low loss applications.

Comprehensive Analysis of Xiaomi Mi 8 GNSS Antenna Performance.

The interest in precise point positioning techniques using smartphones increased with the launch of the world's first dual-frequency L1/L5 GNSS smartphone, Xiaomi Mi 8. The smartphone GNSS antenna is low-cost, sensitive to multipath, and limited by physical space and design. The main purpose of this work is to determine the mechanical location and antenna performance in terms of radiation pattern in an anechoic chamber using a Vector Network Analyzer (VNA) and robotic positioning platform by varying the elevation and azimuth angles between the transmitter and smartphone GNSS antennas; the power received and satellite visibility are developed in an outdoor scenario. The results show a Planar Inverted-F Antenna with an omnidirectional radiation pattern without gain. The L1/E1/B1 and L5/E5a/B2a GNSS antennas are physically located at the top face of the screen, with dimensions of 48 × 17 mm and 60 × 13 mm, respectively. With the screen with line-of-sight toward the sky, L5 satellites have a better signal-noise ratio (SNR), unlike the back side, which loses 99% of the data in the PPP solution. Under multipath scenarios, the L1 GNSS smartphone antenna works with 25% less power than the GPS user segment recommendation, showing high sensitivity to track weak signals.

Dual Frequency Energy Harvesting System Based on Planar Inverted F-shaped Antenna

<p>With the expansion of Internet of things (IoT) scale and the extension of its application fields, node energy acquisition has become one of the constraints on the development and application of IoT technology. Wireless energy acquisition is faced with the challenge of how to enhance power conversion efficiency under low input power in the broadband range. This study aimed to improve the capability of energy collection and transmission in wireless communication, an efficient dual-frequency energy harvesting system was proposed, moreover a novel dual-frequency planar inverted-f antenna (PIFA) and its energy conversion circuit for Radio frequency (RF) energy harvesting were designed by studying the characteristics of ambient RF energy and antenna. The developed antenna is designed and manufactured for GSM 900mhz or DCS 1.8 GHz to harvest the ambient energy provided by nearby devices. It is proved that the new dual-frequency antenna still has high efficiency when the input power is less than -20 dbm, and can maximize the receiving energy. The system works with an energy conversion and storage module to convert weak signals into required voltages, the simulation and test results show that the maximum conversion efficiency of the prototype is about 65% at 920MHZ and 1.8GHz at -20 dBm input power.</p> <p> </p>

Fabrication of an Optically Transparent Planar Inverted-F Antenna Using PEDOT-Based Silver Nanowire Clear Ink with Aerosol-Jet Printing Method towards Effective Antennas

We report the design, fabrication, and experimental characterization of an optically transparent printed planar inverted-F antenna (PIFA) operating at 2.45 GHz using the aerosol jet (AJ) printing method. The proposed antenna was fabricated using a clear conductive ink on glass and Delrin. The antenna exhibits a wide fractional bandwidth (FBW) of 20% centered at 2.45 GHz, with a peak realized gain of −3.6 dBi and transparency of ~80%. The proposed fabrication method provides a cost-effective and scalable solution for manufacturing transparent antennas with potential applications in wireless communication, sensing, and wearable devices operating at mmWave frequencies higher than 30 GHz.

Decoupling Method for Four Closely Spaced Planar Inverted-F Antennas Using Parasitic Elements and Bridge Lines

This study proposed a novel decoupling method for four planar inverted-F antennas (PIFAs) operating at 2.0 GHz (f0). The edge-to-edge and center-to-center spacings of the adjacent PIFAs are extremely small (0.05λ0 and 0.17λ0, respectively), resulting in strong mutual coupling among them. In our previous study, we proposed a structure consisting of parasitic elements (PEs) and a bridge line (BL) for the decoupling of two PIFAs. One attractive feature of the proposed method is that no adjustment of the original structure and size of the PIFAs is necessary. However, as the number of PIFAs increases to four, their decoupling becomes considerably more complicated, and impedance mismatch is also an issue to be considered. Therefore, in this study, PEs and BLs are functionally developed to simultaneously achieve low mutual coupling and improved impedance matching of the four PIFAs. The simulated results showed that loading the proposed PEs and BLs onto the four PIFAs could reduce as well as maintain all mutual coupling for less than -10 dB, and simultaneously improve impedance matching. Therefore, the total antenna efficiency at 2.0 GHz could be significantly improved from 64.2% to 84.8% for PIFA1 and PIFA4, and from 35.9% to 74.2% for PIFA2 and PIFA3. Four PIFAs with PEs and BLs were fabricated and measured to validate the simulation results.

Permittivity-customizable Low-cost Laminated PET Sheet Multilayer Substrate to Design Flexible and Conformal Planar Inverted F Antenna

Abstract: In this article, a Planar Inverted F Antenna (PIFA) has been designed using low-cost commercially available transparent laminated sheets. Energy Dispersive X-ray (EDX) analysis is used to acquire the element composition of the transparent laminated sheet. Methods: The flexibility is attained using a market-available low-cost Polyethylene Terephthalate (PET) sheet as a substrate. The dielectric properties of this non-conventional laminated sheet need to be identified for antenna design and the microstrip ring resonator test method is used to determine the dielectric properties of the multilayer PET sheets. Results: The linear match has been observed on multilayer laminated PET sheets for dielectric properties and radiation characteristics. Adhesive copper foil of a thickness of 0.08 mm has been used as for conducting layer on the PET lamination sheet. As per the literature survey, it is evident that this is the first attempt to use the reported methodology for PIFA design application. The gain of proposed antenna is 5.2dB. Conclusion: The designed flexible antenna has been developed for wearable and IoT applications in 2.45 GHz ISM band. A good match has been observed between the simulated and measured characteristics.

The regulation of high-frequency magnetic properties of NiZnCo ferrite for miniaturized antenna application

Demand for communication devices with miniaturization and high-frequency capability requires materials with high permeability, matching permittivity, low loss, and high operating frequency. In this study, the micromorphology of NiZnCo ferrites synthesized by the co-precipitation method is regulated by changing the sintering temperature, obtaining a domain structure with a high-performance factor (PF). Specifically, the effect of Co ion content on the static and high-frequency magnetic properties of NiZnCo ferrites is analyzed at a sintering temperature of 800 °C. Results reveal that the value of Snoek limit and the magnetocrystalline anisotropy constant of NiZnCo ferrites increase with Co ion content enhances from 0.2 to 0.5, thereby PF elevates from 34.7 GHz (at the maximum operating frequency f0 = 1.04 GHz) to 48.7 GHz (f0 = 2.25 GHz). PF value of Ni0.31Zn0.19Co0.5Fe1.98O4-δ ferrite is measured to be 48.7 GHz at 2.25 GHz. Furthermore, a planar inverted F antenna (PIFA) is designed using Ni0.31Zn0.19Co0.5Fe1.98O4-δ ferrite. The PIFA exhibits a maximum gain of 3.7 dB and a miniaturization rate of 4.6 %. This study holds significant implications for the development of magneto-dielectric materials for use at 2.0 GHz.

Design and development of multiband PIFA antenna for vehicular LTE/5G and V2X communication

This paper aims to introduce a custom-designed multiband planar inverted-F antenna (PIFA) suitable for automotive applications in LTE/5G schemes operating under 6 GHz, as well as Vehicle-to-Everything (V2X) communications. The PIFA antenna has a broad bandwidth capability, resonating from 950 MHz to 6 GHz. The proposed PIFA antenna is divided into three parts: the top, front, and back, resulting in a unique and effective antenna structure. The antenna is fabricated using a substrate made of FR4 material with a dielectric constant of 4.4. The whole measurements of the antenna are 54 × 38 × 25 mm3.The proposed PIFA antenna has been tested and has achieved a voltage standing wave ratio (VSWR) of less than 2 across the entire frequency range of 950 MHz to 6 GHz. Additionally, the maximum gain achieved by the antenna is 7.08 dBi at a frequency of 5.5 GHz, 6.81 dBi at 5.2 GHz, and 6.65 dBi at 5.9 GHz. The antenna also achieved a gain of 6.67 dBi at 3.8 GHz and a gain of 3.31 dBi at 1.7 GHz. Overall, this paper presents a well-designed and effective multiband PIFA antenna that is appropriate for use in vehicular applications. The antenna ability to cover a wide range of bandwidth and achieve high gain makes it an excellent candidate for use in LTE/5G systems and V2X communications.

Simulating the specific absorption rates in different human tissues at 4G frequencies for mobile phones

Employing electromagnetic waves in mobile communication networks has increased the level of human exposure to electromagnetic fields that may result in concerns about health hazards associated involves the soaking up of cellular phone electromagnetic energy. The human body is penetrated by the electromagnetic fields that emit from a cell phone. The specific absorption rate (SAR) that is generated in the human head and body layers usually expresses the thermal effect on human tissue. The main objective of this paper is to investigate the thermal effects of the electromagnetic field induced inside the human head and body through the construction of a simplified model for both. The RF-source and human body models are built by using the ANSYS high-frequency structural simulator (HFSS). A planar inverted-F antenna (PIFA) will use to assign SAR values to different body tissues for the fourth generation (4G) of mobile phone communication at an operational frequency of 2.6 GHz and power radiated of 125 mW. The model is simulated and analyzed to evaluate the SAR induced at different human tissues depending on the source-to-antenna distance and its generated values must not exceed the safe limits for harmful thermal effects.

Compact BLE Antenna With a Modified PIFA Configuration for Wearable EMG Monitor

An antenna mounted underneath the top cover of a wearable device, fed by an ultra-low-profile connector, is proposed for Bluetooth-Low-Energy (BLE) communication at 2.4 GHz. As the antenna is to be used for a wearable device, it is essential that it should be compact in size and tolerant against the nearby medium change. The modified planar inverted-F antenna (PIFA) that we propose consists of a main patch and a parasitic element to broaden the antenna bandwidth. The end of the parasitic element is shorted to miniaturize the antenna to 25 by 10.8 millimeters, fitting well inside a watch-type wearable device. Also, the complete ground layer of the antenna makes it radiate well in the outward direction, and minimally interact with the back-side medium. This results in the reflection coefficient being insensitive to the medium change on the backside. The proposed antenna has a peak gain of 3.62 dBi along with 20% efficiency and the impedance bandwidth of 80 MHz (2.4 ~2.48 GHz). To examine the communicative operation of the antenna in practice, the received signal strength indicator (RSSI) of the complete prototype device with the antenna is measured in various postures and orientations, demonstrating reliable connectivity within a typical indoor distance of 10 meters. Lastly, the antenna is embedded in a wearable device, demonstrating electromyography’s wireless monitoring.

Low-Profile Conical Beam Array Antenna Based on Concentric Annular Planar Inverted-F Antenna Elements

A planar conical beam array antenna with low profile, high gain, and low side lobe level (SLL) is proposed in this letter. The array is composed of three concentric annular planar inverted-F antenna (APIFA) elements, each of which is excited by uniform distributed feeding points with the same excitation amplitude and phase and thus obtain an axisymmetric conical beam. Shorting pins and cambered slots are employed on the APIFA element to realize impedance matching for a given number of feeding points. Synthesis of conical beam for the array can be flexibly realized by adjusting the excitation amplitudes and phases of the elements. A prototype with a low profile of 0.11 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is designed, fabricated, and measured. Measured results show that the prototype achieves 11.2% (4.71 ∼ 5.27 GHz) -10-dB impedance bandwidth. Within the impedance bandwidth, a stable gain of 11.3 to 12.7 dBi, a stable beam-pointing angle (BPA) of about 15°, and a low SLL of less than -12.5dB is obtained, indicating good conical beam performance.

Design of an Enhanced Isolation 8-Unit MIMO Antenna for Smartphones Operating in 5G nR and LTE 42 Bands

A miniaturized enhanced isolation 8-unit MIMO antenna for smartphones is proposed in this paper. The units are planar inverted-F antennas with the same structure, and we use the slotting method and shorted probe to miniaturize them. The size of every unit is 14 × 6 mm2 (0.149 × 0.064λ2). We insert an L-shaped decoupling element into the middle of adjacent radiating elements and connect the decoupling element to the GND. Note that the decoupling elements are on the outer side of the substrate, and the radiating elements are on the inner side of the substrate. Finally, a prototype is fabricated and measured. The measured results show that the bandwidth of the MIMO antenna is from 3.0 GHz to 5.3 GHz (55.4%), which fully supports the n77, n78, and n79 in the 5G nR frequency band and the 4G LTE 42 frequency band (S11 less than −6 dB). The measured isolation of the MIMO antenna is greater than 25 dB by using the decoupling method in this paper. The envelope correlation coefficient of the proposed MIMO antenna is less than 0.08, its radiation efficiency is greater than 50%, and its gain is between 4.2 and 5.3 dBi in the whole operating frequency band.

MIMO 5G Smartphone Antenna with Tri-Band and Decoupled Elements.

In this article, a miniaturized antenna is proposed for 4G/5G multiple input, multiple output (MIMO) applications for smartphones. The proposed antenna is composed of an inverted L-shaped antenna with decoupled elements to cover 4G (2000-2600 MHz), and a planar inverted-F antenna (PIFA) with a J-slot to cover 5G (3400-3600 MHz and 4800-5000 MHz). Furthermore, to achieve the purposes of miniaturization and decoupling, the structure adopts a feeding stub, shorting stub, and outstanding floor, additionally adding the slot to the PIFA, to generate additional frequency bands. Due to the advantages such as multiband operation, MIMO configuration for 5G communications, high isolation, and a compact structure, the proposed antenna design is attractive for 4G/5G smartphones. The antenna array is printed on an FR4 dielectric board, measuring 140 × 70 × 0.8 mm3, with the 4G antenna located on a top 15 mm-long headroom.

SAR Calculation in a Child Seven-Layer Head Model at 2.1 and 2.6 GHz

Health and safety concerns have grown in recent years due to the increasing frequency bands and the demand for wireless communication apparatus. Electromagnetic (EM) radiation breakthrough from Radio frequency (RF) into the human head is an issue that needs to be addressed. Radiation from RF sources can cause serious biological hazards inside the human body. This study measures the average Specific Absorption Rate in a 7-year-old child's head tissues using the ANSYS HFSS software and varying the distance from the source to the antenna in order to address these issues. SAR levels of phones sold should be below certain standard limits. We have used an internal antenna of a mobile phone It's a planar inverted F-antenna (PIFA) with a connected feeding structure.&#x0D;

Miniaturized On-Ground 2.4 GHz IoT LTCC Chip Antenna and Its Positioning on a Ground Plane

This paper presents a very low-profile on-ground chip antenna with a total volume of 0.075λ0× 0.056λ0× 0.019λ0 (at f0 = 2.4 GHz). The proposed design is a corrugated (accordion-like) planar inverted F antenna (PIFA) embedded in low-loss glass ceramic material (DuPont GreenTape 9k7 with ϵr = 7.1 and tanδ = 0.0009) fabricated with LTCC technology. The antenna does not require a clearance area on the ground plane where the antenna is located, and it is proposed for 2.4 GHz IoT applications for extreme size-limited devices. It shows a 25 MHz impedance bandwidth (for S11 < -6 dB), which means a relative bandwidth of 1%). A study in terms of matching and total efficiency is performed for several size ground planes with the antenna installed at different positions. The use of characteristic modes analysis (CMA) and the correlation between modal and total radiated fields is performed to demonstrate the optimum position of the antenna. Results show high-frequency stability and a total efficiency difference of up to 5.3 dB if the antenna is not placed at the optimum position.

Design and Optimization of Planar Inverted F Antenna (PIFA) for Wireless Applications

For 5G communication networks, including Long-Term Evolution Advanced mobile communication services, PIFA antenna is proposed. The proposed antenna structure is consisting of substrate, ground plane, shorting plate and feeding post connected to the ground plane. This antenna has been design based on a FR-4has relative permittivity of 4.3 it has a volume of (120601.5) mm3. The experimental results of the Planar Inverted F Antenna (PIFA) that have been measured at the range from (3-4 ) GHz of frequency experimentally using the Site Master (Anritsu S362E), it has been demonstrated that the return loss, bandwidth, VSWR, and impedance are −41.15dB, 510 MHz, 1.04and 48.414Ω respectively at resonant frequency 3.5GHz. The theoretical and practical values are so close to each other which justifies the antenna's excellent fit