Showing papers on "Coaxial antenna published in 2015"

Compact MIMO Antenna for Portable UWB Applications With Band-Notched Characteristic

Abstract: A multiple-input-multiple-output (MIMO) band-notched antenna with a compact size of only $22 \times 36\;\mathrm{mm}^2 $ is proposed for portable ultrawideband (UWB) applications. The antenna consists of two square monopole-antenna elements, a T-shaped ground stub, a vertical slot cut on the T-shaped ground stub to reduce mutual coupling, and two strips on the ground plane to create a notched frequency band. Simulation and measurement are used to study the antenna performance in terms of impedance matching, isolation between the two input ports, radiation pattern, efficiency, peak gain, and envelope correlation coefficient. Results show that the antenna can operate from 3.1 to more than 11 GHz with a notched band in 5.15–5.85 GHz. In the center notched frequency, the efficiency drops to 7%, indicating a good interference suppression performance. The mutual coupling is less than $- 15\;\mathrm{dB}$ and the envelope correlation coefficient is less than 0.1. The performances of the MIMO antenna when installed on a PCB with a standard size, with an USB connector and device housing, are also studied. Results show that the proposed MIMO antenna is a good candidate for portable UWB applications.

Remote rf power system with low profile transmitting antenna

Abstract: An antenna assembly includes: an antenna including: a metal signal layer having a radiating surface; and a feed port; and a waveguide surrounding the antenna and configured to guide electromagnetic energy transmitted from the radiating surface in a direction away from the antenna; and a controller module connected to the feed port and configured to drive the antenna to transmit electromagnetic energy from the radiating surface; wherein the antenna, waveguide, and controller module are configured such that, when the controller module drives the antenna, the transmitted electromagnetic energy matches a reception characteristic of an implantable device and is sufficient for the implantable device to create one or more electrical pulses of sufficient amplitude to stimulate neural tissue of a patient, solely using electromagnetic energy received from the antenna, when the implantable device is located at least 10 centimeters away from the antenna.

A Compact, Wideband Circularly Polarized Co-designed Filtering Antenna and Its Application for Wearable Devices With Low SAR

Abstract: A compact circularly polarized (CP) co-designed filtering antenna is reported. The device is based on a patch radiator seamlessly integrated with a bandpass filter composed of coupled stripline open-loop resonators, which are designed together as a system. In the proposed design, the patch functions simultaneously as the radiator and the last stage resonator of the filter, resulting in a low-profile integrated radiating and filtering module with a small overall form factor of $\mathbf{0.53{\lambda _0} \times 0.53{\lambda _0} \times 0.07{\lambda _0}}$ . It is shown that the filtering circuit not only ensures frequency selectivity but also provides impedance matching functionality, which serves to broaden both the impedance and axial ratio bandwidths. The designed filtering antenna was fabricated and measured, experimentally achieving an $\mathbf{{S_{11}} , an axial ratio of less than 3 dB and a gain higher than 5.2 dBi over a bandwidth from 3.77 to 4.26 GHz, i.e., around 12.2%, which makes it an excellent candidate for integration into a variety of wireless systems. A linearly polarized version of the integrated filtering antenna was also demonstrated. In addition, further full-wave simulations and experiments were carried out to verify that the designed CP filtering antenna maintains its properties even when mounted on different positions of the human body with various body gestures. The stable impedance and radiation properties also make it a suitable candidate as a wearable antenna for off-body wireless communications.

Compact Offset Microstrip-Fed MIMO Antenna for Band-Notched UWB Applications

Abstract: A compact multiple-input–multiple-output (MIMO) antenna is presented for ultrawideband (UWB) applications with band-notched function. The proposed antenna is composed of two offset microstrip-fed antenna elements with UWB performance. To achieve high isolation and polarization diversity, the antenna elements are placed perpendicular to each other. A parasitic T-shaped strip between the radiating elements is employed as a decoupling structure to further suppress the mutual coupling. In addition, the notched band at 5.5 GHz is realized by etching a pair of L-shaped slits on the ground. The antenna prototype with a compact size of $38.5 \times38.5~\hbox{mm}^{2}$ has been fabricated and measured. Experimental results show that the antenna has an impedance bandwidth of 3.08-11.8 GHz with reflection coefficient less than $-10~\hbox{dB}$ , except the rejection band of 5.03-5.97 GHz. Besides, port isolation, envelope correlation coefficient and radiation characteristics are also investigated. The results indicate that the MIMO antenna is suitable for band-notched UWB applications.

Cylindrical Slot FSS Configuration for Beam-Switching Applications

Abstract: A novel design for a beam-switching antenna using active cylindrical slot frequency selective surface (ACSFSS) is presented. The antenna system is composed of an omnidirectional monopole antenna and the ACSFSS, which employs a new technique of switching slot arrays. The ACSFSS is made up of 12 columns with 8 slots each, dividing the cylinder by 30 $^{\circ}$ . To steer the beam of the antenna the diodes are set off and on, so that the radiation pattern of the antenna is determined by the number of off state columns. To estimate the general dimension of the cylindrical FSS, an equivalent metallic reflector is introduced and optimized, and then parametric studies for the unit cell dimensions are discussed. The fabricated prototype works within the WLAN band, centered around 2.45 GHz, and can agilely select either a narrow-beam or wide-beam operating mode. Simulation and measurements confirm the operation of the ACSFSS antenna, with good matching and gain observed. In particular, the narrow-beam mode $-$ 3 dB beamwidth is 47 $^{\circ}$ which offers enhanced angular resolution compared with other reported beam-sweeping work.

A Novel Dual-Band, Dual-Polarized, Miniaturized and Low-Profile Base Station Antenna

Abstract: In this paper, a novel dual-band, dual-polarized, miniaturized and low-profile base station antenna operating in the frequency bands of 820–960 and 1710–2170 MHz is designed. Elements are arranged such that high-frequency elements are embedded in low frequency elements to reduce volume. A baffle is used to reflect the transmitted power density in the forward direction and also improve isolation between elements. Therefore, surrounding isolation baffles and rectangular baffles are appended around high-frequency elements and low-frequency elements, respectively. The diameter of the proposed antenna cover is only 200 mm, which is smaller than the existing antenna diameter of 280 mm. Compared with the other commonly used antennas, the proposed antenna also has some advantages such as concealment and low profile using a tubular form of radome, which can easily integrate the proposed antenna with the surrounding environment. The measured results verify that the proposed antenna meets the stringent design requirements: voltage standing wave ratio (VSWR) is less than 1.3, the isolation is greater than 30 dB, and the pattern parameters also meet telecommunications industry standards.

Wideband RCS Reduction of a Microstrip Antenna Using Artificial Magnetic Conductor Structures

Abstract: A design approach aimed at reducing the radar cross section (RCS) of microstrip antenna in wide frequency band is proposed. First, two different artificial magnetic conductor (AMC) unit cells are designed to obtain 180 $^\circ $ ( $ \pm 30^\circ $ ) reflection phase difference over broadband frequency range. Then, chessboard configuration is structured with the two AMC unit cells and is applied to a microstrip antenna for RCS reduction. The simulated results indicate that the proposed antenna possesses remarkable RCS reduction from 8.0 GHz to 20.0 GHz for both polarizations, covering the working band of the original antenna. The maximum reduction is 31.9 dB. Moreover, the radiation performance of the antenna has been well kept. Measured results of the fabricated prototype are in good agreement with the simulations.

Crossed Dipole Loaded With Magneto-Electric Dipole for Wideband and Wide-Beam Circularly Polarized Radiation

Abstract: A crossed dipole that is loaded with a magneto-electric dipole to produce the wideband and wide-beam circularly polarized radiation characteristics is proposed. The crossed dipole is incorporated with double-printed vacant-quarter rings to feed the antenna. The antenna is backed by a metallic cavity to provide a unidirectional radiation pattern with a wide axial-ratio (AR) beamwidth and a high front-to-back ratio. Experimental results showed that the prototype with an overall size of $120\times 120\times30.5~\hbox{mm}^3$ has a $\vert { S}_{11}\vert bandwidth of 1.274–2.360 GHz and a 3-dB AR bandwidth of 1.39–1.82 GHz. The antenna showed a right-hand circular polarization (CP) radiation with a very wide 3-dB AR beamwidth ( $>165^{\circ}$ ) and a high radiation efficiency ( $ > 94\%$ ) within the operational bandwidth.

Dual-Band Textile MIMO Antenna Based on Substrate-Integrated Waveguide (SIW) Technology

Abstract: A dual-band textile antenna for multiple-input–multiple-output (MIMO) applications, based on substrate-integrated waveguide (SIW) technology, is designed. The fundamental SIW cavity mode is designed to resonate at 2.4 GHz. Meanwhile, the second and third modes are modified and combined by careful placement of a via within the cavity to enable wideband coverage in the 5-GHz WLAN band. The simple antenna topology can be fabricated fully using textiles in a planar form, ensuring reliability and comfort. Numerical and experimental results indicate satisfactory antenna performance when worn on body in terms of impedance bandwidth, radiation efficiency, and specific absorption ratio (SAR). In order to validate its potential for MIMO applications, two elements of the proposed SIW antenna are arranged in six configurations to study the performance in terms of mutual coupling and envelope correlation. It is observed that the placement of the shorted edges of the two elements adjacent to each other produces the lowest mutual coupling and consequently the best envelope correlation.

Wearable Dual-Band Magneto-Electric Dipole Antenna for WBAN/WLAN Applications

Abstract: A wearable dual-band magneto-electric dipole antenna is proposed. Two U-shaped slots are introduced on a dipole and the resulting electric and magnetic resonances are combined with the aim to produce a dual band with wideband characteristics. The antenna is fabricated fully using textiles, except for the feeding connector. Simulations and measurements confirm the wide bandwidth and a low backward radiation in both the lower and the upper band. The antenna is robust and not very sensitive to bending when worn by the user. The specific absorption rate is studied numerically and proven to be well below the European limit of 2 W/kg.

A Compact Kapton-Based Inkjet-Printed Multiband Antenna for Flexible Wireless Devices

Abstract: A low-cost inkjet-printed multiband antenna envisioned for integration into flexible and conformal mobile devices is presented. The antenna structure contains a novel triangular iterative design with coplanar waveguide (CPW) feed, printed on a Kapton polyimide-based flexible substrate with dimensions of $ 70\times 70\times 0.11~\hbox{mm}^{\bf 3}$ . The antenna covers four wide frequency bands with measured impedance bandwidths of 54.4%, 14%, 23.5% and 17.2%, centered at 1.2, 2.0, 2.6 and 3.4 GHz, respectively, thus, enabling it to cover GSM 900, GPS, UMTS, WLAN, ISM, Bluetooth, LTE 2300/2500 and WiMAX standards. The antenna has omnidirectional radiation pattern with a maximum gain of 2.1 dBi. To characterize the flexibility of the antenna, the fabricated prototype is tested in convex and concave bent configurations for radii of 78 mm and 59 mm. The overall performance remains unaffected, except a minor shift of 20 MHz and 60 MHz in S11, for concave bending at both radii. The compact, lightweight and conformal design as well as multiband performance in bent configurations, proves the suitability of the antenna for future electronic devices.

Low-Cost Wideband and High-Gain Slotted Cavity Antenna Using High-Order Modes for Millimeter-Wave Application

Abstract: A novel single-fed low-cost wideband and high-gain slotted cavity antenna based on substrate integrated waveguide (SIW) technology using high-order cavity modes is demonstrated in this paper. High-order resonant modes ( ${\text T}{{\text E}_{{130}}}$ , ${\text T}{{\text E}_{{310}}}$ , ${\text T}{{\text E}_{{330}}}$ ) inside the cavity are simply excited by a coaxial probe which is located at the center of the antenna. Energy is coupled out of the cavity by a $3 \times 3$ slot array etched on the top surface of the cavity. Two antennas with different polarizations are designed and tested. Measured results show that the linearly polarized prototype achieves an impedance bandwidth $\left(\vert{{\text S}_{{\text 11}}}\vert of $> {26}\% $ (28 to 36.6 GHz), and a 1-dB gain bandwidth of 14.1% (30.3 to 34.9 GHz). In addition, a measured maximum gain of 13.8 dBi and radiation efficiency of 92% are obtained. To generate circularly polarized radiation, a rotated dipole array is placed in front of the proposed linearly polarized antenna. Measured results show that the circularly polarized antenna exhibits a common bandwidth (10-dB return loss bandwidth, 3-dB axial ratio bandwidth, and 1-dB gain bandwidth) of 11%.

Design and Demonstration of an Electronically Scanned Reflectarray Antenna at 100 GHz Using Multiresonant Cells Based on Liquid Crystals

Abstract: The design, fabrication, and measured results are presented for a reconfigurable reflectarray antenna based on liquid crystals (LCs) which operates above 100 GHz. The antenna has been designed to provide beam scanning capabilities over a wide angular range, a large bandwidth, and reduced side-lobe level (SLL). Measured radiation patterns are in good agreement with simulations, and show that the antenna generates an electronically steerable beam in one plane over an angular range of 55° in the frequency band from 96 to 104 GHz. The SLL is lower than $-\mathbf{13}\;\mathbf{dB}$ for all the scan angles and $-\mathbf{18}\;\mathbf{dB}$ is obtained over 16% of the scan range. The measured performance is significantly better than previously published results for this class of electronically tunable antenna, and moreover, verifies the accuracy of the proposed procedure for LC modeling and antenna design.

A New Wideband Circularly Polarized Stair-Shaped Dielectric Resonator Antenna

Abstract: A circularly polarized stair-shaped dielectric resonator antenna (DRA) with a wideband circular polarization (CP) radiation is introduced for wireless local area network (WLAN) applications. This antenna is implemented by using two rectangular dielectric resonators (DRs), which are joined together to form a stair-shaped dielectric resonator antenna (DRA). In this structure, the excitation of multiple orthogonal modes leads to a wideband CP bandwidth. Measured results show that the proposed antenna has an axial ratio (AR) bandwidth of 22% (5.2–6.5 GHz), an impedance bandwidth of 37% (4.6–6.7 GHz), and a peak gain of 5.7 dB. In addition, the antenna radiation efficiency of more than 90% is achieved.

Structure and Computationally Efficient Simulation-Driven Design of Compact UWB Monopole Antenna

Abstract: In this letter, a structure of a small ultra-wideband (UWB) monopole antenna, its design optimization procedure as well as experimental validation are presented. According to our approach, antenna compactness is achieved by means of a meander line for current path enlargement as well as the two parameterized slits providing additional degrees of freedom that help to ensure good impedance matching. For the sake of reliability, the antenna design process (simultaneous adjustment of multiple geometry parameters) is carried out using high-fidelity EM analyses. Surrogate-based optimization involving an auxiliary coarse-discretization EM model it utilized to accomplish the design in practical timeframe. Penalty function approach allows us to reduce the antenna footprint (to only $15.8 \times 22~\hbox{mm}^2$ ) while maintaining acceptable reflection in the UWB frequency range. Experimental validation of the design is also provided.

Differential Microstrip Antenna for RF Energy Harvesting

Abstract: A differential microstrip antenna with improved gain for RF energy harvesting is presented in this paper. The developed antenna can be used in either center grounded or differential configuration. The antenna is designed and fabricated for GSM900 band (890–960 MHz). The antenna has a gain of 8.5 dBi at the center frequency and exhibits VSWR $\boldsymbol{\leq} 2$ for frequencies between 870 MHz to 1.05 GHz. The efficiency of the antenna is 80%. The developed antenna finds its application in energy harvesting, RFID tags and in wireless communication circuits, where differential inputs/outputs are needed. A complete differential RF energy harvesting system with a peak efficiency of 65.3% for a load of $3 {\mathbf{k}}\boldsymbol{\Omega}$ is also developed.

A Cognitive Radio Reconfigurable MIMO and Sensing Antenna System

Abstract: A planar, compact, single-substrate, multiband, frequency-reconfigurable multiple-input–multiple-output (MIMO) antenna system is presented. The proposed antenna elements are integrated with an ultrawideband (UWB) sensing antenna to develop a complete antenna platform for cognitive radio (CR) applications. The dual-element MIMO antenna is integrated with p-i-n and varactor diodes for frequency reconfigurability. Two modes of selection are used for the MIMO antenna system reconfigurability along with varactor tuning to sweep the frequency over a wide band especially below 1 GHz. The proposed sensing antenna is used to cover a wide range of frequency bands from $720\sim3440~\hbox{MHz}$ . The complete system comprising the multiband reconfigurable MIMO antennas and UWB sensing antenna for CR applications is proposed with a compact form factor. The antenna system is developed on a single substrate area of dimensions $65\times120\times1.56~\hbox{mm}^3$ .

A Water Dense Dielectric Patch Antenna

Abstract: A novel water dense dielectric patch antenna (DDPA) fed by an L-shaped probe is proposed and investigated. In contrast to the water antennas in the literature, including the water monopole and the water dielectric resonator antenna, the operation mechanism of the proposed water DDPA is similar to the conventional metallic patch antenna. The antenna is excited in a mode like the TM $_{{\textrm {10}}}$ mode of the rectangular patch antenna. An L-shaped probe, which is widely used for the conventional patch antenna, is used to excite the water DDPA. A study on the bandwidth performance of the proposed design reveals that wide bandwidth can be achieved for the antenna by choosing a thick supporting substrate between the water patch and the ground plane. A prototype is fabricated to confirm the correctness of the design. An impedance bandwidth of 8%, maximum gain of 7.3 dBi, radiation efficiency up to 70%, and symmetrically unidirectional patterns with low backlobe and low cross polarization levels are obtained. Furthermore, owing to the transparency of the water patch, the proposed water DDPA can be conveniently integrated with the solar cells to realize a dual-function design. Measurements on the prototype demonstrate that the existence of the solar cells does not significantly affect the performance of the antenna and vice versa.

An Origami Reconfigurable Axial-Mode Bifilar Helical Antenna

Abstract: This communication presents a new reconfigurable origami bifilar helical antenna. This antenna can change its operating frequencies by changing its height. Also, analytical equations for the design of such antennas are derived based on an equivalent model of a standard helical antenna. An origami bifilar helical antenna is designed and its performance is verified using simulations and measurements.

Broadband Circularly Polarized Patch Antenna With Parasitic Strips

Abstract: A patch antenna with parasitic strips is presented for wideband circular polarization. In order to broaden the axial-ratio (AR) bandwidth of the original corner-truncated patch, four parasitic strips are sequentially rotated and gap-coupled around the patch. A capacitive-coupled feed with a small disc on the top of the feeding probe is utilized to obtain a wide impedance-matching bandwidth. Moreover, another disc-loaded shorting pin is placed at the center of the antenna to adjust the squint beams and improve the gains along $ + z$ -axis. Measured results show that the proposed antenna with a low profile of $0.13{\lambda _0}$ obtains a global bandwidth of 24% (2.32–2.95 GHz) for $\vert{S_{11}}\vert , ${\rm AR} , and average gain of 8 dBic.

A 3-D Millimeter-Wave Filtering Antenna With High Selectivity and Low Cross-Polarization

Abstract: A three-dimensional (3-D) filtering antenna with features of high selectivity and low cross-polarization is proposed and experimentally verified in this communication. Thanks to the vertically 3-D integration, the high selectivity at either frequency sides of the filtering antenna is achieved by a novel cross-coupling scheme between in-band and out-of-band modes in a single cavity located in the lower substrate, while the low cross-polarization in the far-field is realized due to the symmetric feed and radiators on a cavity-backed dual-slot antenna at the upper substrate. In our design, the cavity-backed dual-slot antenna performs not only a radiator but also the last resonator of the bandpass filter (BPF). A prototype is demonstrated at Ka -band with a center frequency of 31.495 GHz and fractional bandwidth of 1.56%. Two radiation nulls [transmission zeros (TZs)] at either frequency band edges can be observed and a cross-polarization level lower than $- 30\,\mathrm{dB}$ is obtained.

Wideband Magneto-Electric Dipole Antenna for 60-GHz Millimeter-Wave Communications

Abstract: A new wideband magneto-electric dipole antenna is proposed for 60-GHz millimeter-wave applications. This antenna features wideband and stable gain characteristics. The low cross polarization and low back radiation are obtained owing to its complementary antenna structure. The prototype of the single element was built using the low-cost single-layer printed circuit board (PCB) technology. The proposed antenna exhibits an impedance bandwidth of 51% ( ${\rm SWR} \leq 2$ ) and a gain of approximately 8 dBi.

A Circularly Polarized Antenna by Using Rotated-Stair Dielectric Resonator

Abstract: In this letter, a wideband compact circularly polarized (CP) dielectric resonator antenna (DRA) is proposed. This antenna consists of two rectangular dielectric layers that are stacked with a rotation angle $\varphi $ relative to its adjacent bottom layer. The antenna is excited by an aperture coupled through a slot cutting on the ground plane. The rotated-stair configuration of DRA contributes dual broadside CP radiating modes and results in a noticeable enhancement in the axial ratio (AR) bandwidth. The proposed antenna achieves 31% impedance bandwidth and 18.2% AR bandwidth. The average gain within the AR bandwidth is 4.5 dBi with less than 0.5-dB variation. Moreover, the proposed dielectric resonator antenna has a low-profile structure. This work demonstrates a CP bandwidth broadening technique for the DRA. The potential applications of the antenna are 5G Wi-Fi and satellite communication systems.

A 2.45 GHz Phased Array Antenna Unit Cell Fabricated Using 3-D Multi-Layer Direct Digital Manufacturing

Abstract: This paper reports on the design, fabrication and characterization of a 3-D printed RF front end for a 2.45 GHz phased array unit cell. The printed unit cell, which includes a circularly-polarized dipole antenna, a miniaturized capacitive-loaded open-loop resonator filter and a 4-bit phase shifter, is fabricated using a direct digital manufacturing (DDM) approach that integrates fused deposition of thermoplastic substrates with micro-dispensing for deposition of conductive traces. The individual components are combined in a passive phased array antenna unit cell comprised of seven stacked substrate layers with seven conductor layers. The measured return loss of the unit cell is ${>}12$ dB across the 2.45 GHz ISM band and the measured gain is ${-}11$ dBi including all components. Experimental and simulation-based characterization is performed to investigate electrical properties of as-printed materials, in particular the inhomogeneity of printed thick-film conductors and substrate surface roughness. The results demonstrate the strong potential for fully-printed RF front ends for light weight, low cost, conformal and readily customized applications.

3-D Printed Microwave Patch Antenna via Fused Deposition Method and Ultrasonic Wire Mesh Embedding Technique

Abstract: In this work, the design, fabrication and characterization of a 3-D printed microwave patch antenna is presented The antenna is fabricated by combining fused filament fabrication method for the dielectric part and ultrasonic metal wire mesh embedding approach for the conductor part Full wave finite-element simulations for different wire mesh structures and also the entire antenna have been done to make sure the embedded wire mesh has good performance at microwave frequency A microstrip patch antenna working around 75 GHz is printed and characterized to demonstrate the efficiency and accuracy of this technique The measured reflection coefficient shows a good resonance peak at 75 GHz The measured gain of this antenna is 55 dB at the resonance frequency Good agreement between simulation and measurement is obtained in both reflection coefficient and radiation pattern

340 GHz On-Chip 3-D Antenna With 10 dBi Gain and 80% Radiation Efficiency

Abstract: This paper discusses the design methodologies of a 340 GHz on-chip 3-D antenna. Firstly, a high-gain and high-radiation efficiency substrate integrated waveguide (SIW) cavity backed on-chip antenna is designed using a standard 0.13- $\mu{\hbox{m}}$ SiGe BiCMOS technology. Then, a low-permittivity supporter and a dielectric resonator (DR) are vertically stacked on the proposed on-chip antenna, forming a 3-D Yagi-like antenna to further enhance the gain and radiation efficiency. The measurements showed that the proposed antenna achieved a peak gain of ${\sim}$ 10 dBi and radiation efficiency of ${\sim}$ 80% at 340 GHz; the impedance bandwidth is ${\sim}$ 12% with the use of dielectric resonator antenna (DRA) and the Yagi-like structure. The antenna size is ${\sim} {\hbox{0.7}}\times {\hbox{0.7}}\ {\hbox{mm}}^{2}$ .

Substrate Integrated Magneto-Electric Dipole Antenna for 5G Wi-Fi

Abstract: In this communication, a new technique—tapered H-shaped ground, is proposed to reduce the thickness of a magneto-electric (ME) dipole antenna By employing the proposed technique, the antenna height of the ME dipole antenna is reduced from 025 to 011 $\lambda_{{\bf 0}}$ (where $\lambda_{{\bf 0}}$ is the wavelength of 55 GHz) This new antenna structure can be easily realized by the multi-layer printed circuit board (PCB) technology, which is low cost and easy to fabricate Measured results show that this antenna has an impedance bandwidth of 1874% for ${\rm VSWR} \le 2$ (498 to 601 GHz) Stable radiation patterns with low back radiation and low cross polarization radiation are achieved across the entire operating bandwidth for 5G Wi-Fi

Planar Endfire Circularly Polarized Antenna Using Combined Magnetic Dipoles

Abstract: A novel planar circularly polarized antenna with endfire radiation beam in parallel with the antenna substrate’s plane is proposed. The operation principle of the antenna is analyzed and design guidelines are laid down. Then, an optimized loop-aperture combined antenna is designed and demonstrated to exhibit an endfire beam in parallel with its plane within 5.74-5.88 GHz for $\vert{{\rm S}_{11}}\vert$ lower than $-10~\hbox{dB}$ and axial ratio smaller than 3 dB. The proposed antenna can be used as a low-profile, cost-effective, hand-held reader antenna for radio frequency identification systems .

Developing flexible 3D printed antenna using conductive ABS materials

Abstract: This paper presents the feasibility of conductive acrylonitrile butadiene styrene (ABS) materials in the fabrication of flexible three-dimensional (3D) antennas using additive manufacturing method. To demonstrate this application a bowtie antenna with coplanar waveguide (CPW) feed structure has been designed and measured. The prototype of the antenna has been fabricated using Makerbot® dual 3D printer and flexible polylactic acid (PLA) and ABS filaments for dielectric and conductive parts of the antenna, respectively. To our knowledge, this is the first reported antenna fabricated with conductive ABS material. The dielectric properties of the PLA and ABS filaments have been measured using Agilent performance probe. The fabricated antenna possesses compact size, light-weight and mechanically flexible structure. In addition it achieves wide bandwidth of 24.18 % at the center frequency of 7.81 GHz.

Microstrip patch antenna miniaturisation techniques: a review

Abstract: The microstrip patch antenna (MPA) has been in use and has been studied extensively during the past three decades. This antenna, which consists of a metallic patch printed on a dielectric substrate over a ground plane, offers several advantages including ease of design and fabrication; low profile and planar structure; and ease of integration with circuit elements. The minimum dimension of a conventional MPA is in the order of half a wavelength. In recent years, with the advent of new standards and compact wireless devices, there has been a need to reduce the size of this type of antenna. This study discusses some of the principal techniques that have been reported in the literature to reduce the size of an MPA. These miniaturisation techniques include material loading, reshaping the antenna, shorting and folding, introducing slots and defects in the ground plane and the use of metamaterials. The major features and drawbacks of each of these approaches are highlighted in this study along with their effects on the antenna performance metrics.