scholarly journals A Flexible Broadband CPW-Fed Circularly Polarized Biomedical Implantable Antenna With Enhanced Axial Ratio Bandwidth

Author(s):  
Sarosh Ahmad ◽  
Bilal Manzoor ◽  
Salman Naseer ◽  
Adnan Ghaffar ◽  
Mousa Hussein

Abstract Implantable antennas have a vital role in biomedical telemetry applications. Therefore, a compact low-profile circularly polarized biomedical implantable antenna operational in industrial, scientific, and medical (ISM) band at 2.45 GHz is reported. The presented antenna is fed by a modified co-planar waveguide (CPW) technique to keep the size of the antenna compact. The radiating monopole consists of a slotted rectangular patch with one slot at an angle of 45 degree and truncated small patch on the left end of the CPW ground plane to make the antenna circularly polarized at the required frequency band. A flexible Roger Duroid RT5880 substrate (εr = 2.2, tanδ = 0.0009) with the standard thickness of 0.254 mm is used to achieve bending abilities. The complete volume of the designed antenna is 21 mm × 13.5 mm × 0.254 mm (0.25 × 0.16 × 0.003 ). The antenna covers the bandwidth from 2.35-2.55 GHz (200 MHz) in free space while from 1.63 GHz to 2.8 GHz (1.17 GHz) inside skin tissue. As the designed antenna is operational in skin tissue with larger bandwidth, the bending analysis along the (x & y)-axis is also analyzed through the simulation. A good agreement between the simulation and measurements of the bended antenna is observed. The measured -10dB impedance bandwidth and the 3dB axial ratio (AR) bandwidth inside skin-mimicking gel are 47.7% and 53.8%, respectively at 2.45 GHz frequency band. Finally, the specific absorption rate (SAR) values are also analyzed through simulations, and it is 0.78 W/kg inside skin over 1 g of mass tissue. The proposed SAR values are less than the limit of the federal communication commission (FCC). This antenna is miniaturized and an ideal applicant for the biomedical implantable applications.

Author(s):  
Sanyog Rawat ◽  
Kamlesh Kumar Sharma

<p class="Abstract"><span style="font-weight: normal;">In this paper a new geometry of patch antenna is proposed with improved bandwidth and circular polarization. The radiation performance of circularly polarized rectangular patch antenna is investigated by applying IE3D simulation software and its performance is compared with that of conventional rectangular patch antenna.</span> <span style="font-weight: normal;">Finite Ground truncation technique is used to obtain the desired results. The simulated return loss, axial ratio and smith chart with frequency for the proposed antenna is reported in this paper. It is shown that by selecting suitable ground-plane dimensions, air gap and location of the slits, the impedance bandwidth can be enhanced upto 10.15 % as compared to conventional rectangular patch (4.24%) with an axial ratio bandwidth of 4.05%.</span></p><p> </p><p> </p>


Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammad Pourbagher ◽  
Changiz Ghobadi ◽  
Javad Nourinia ◽  
Rahim Naderali

Purpose To achieve right-hand circular polarization (RHCP), a 3-dB Wilkinson power divider with a λ/4 phase shifter is used. The crossed-dipoles are placed at almost λ/4 elevation on the ground plane and connected to two coaxial cables. Experiments show that the impedance bandwidth of 49.40% (913.7–1,513.1 MHz) and axial ratio bandwidth (ARBW) of 22.88% (1,145.8–1,441.8 MHz) are achieved. Design/methodology/approach In this study, a wideband crossed-dipole antenna with circularly polarized (CP) radiation for L-band satellite and radar applications is presented. The proposed CP antenna comprises two orthogonally placed printed dipoles, a quadrature coupler and a box-shaped ground plane. Findings Furthermore, by fixing the box-shaped ground plane under the radiators, 5.13 dBic RHCP peak gain at 1,300 MHz and maximum half-power beamwidth (HPBW) of 84.5° at 1,170 MHz are realized for the antenna. Originality/value Eight metallic walls are connected to four corners of the substrate to stabilize the radiation properties in this study. Results show that the ARBW and front-to-back ratio are improved and the maximum HPBW around 127° across the operating frequency band is achieved. The proposed CP antenna is a good candidate for Global Positioning System (GPS) L2 (1.227 GHz), GPS L5 (1.176 GHz) and air route surveillance radar system at 1,215–1,390 MHz frequency band.


2012 ◽  
Vol 1 (2) ◽  
pp. 97-106
Author(s):  
Sanyog Rawat ◽  
K K Sharma

In this paper a new geometry of circularly polarized patch antenna is proposed with improved bandwidth. The radiation performance of proposed patch antenna is investigated using IE3D simulation software and its performance is compared with that of conventional rectangular patch antenna. The simulated return loss, axial ratio and impedance with frequency for the proposed antenna are reported in this paper. It is shown that by selecting suitable ground-plane dimensions, air gap and location of the slots, the impedance bandwidth can be enhanced upto 10.15% as compared to conventional rectangular patch (4.24%) with an axial ratio bandwidth of 4.05%.DOI: 10.18495/comengapp.12.097106


2019 ◽  
Vol 11 (08) ◽  
pp. 835-843 ◽  
Author(s):  
Amit Birwal ◽  
Sanjeev Singh ◽  
Binod Kumar Kanaujia ◽  
Sachin Kumar

AbstractThe paper presents a new coplanar waveguide (CPW)-fed rectangular patch antenna with a square-shaped ground plane that can be employed in modern advanced navigation systems. For realizing broad impedance bandwidth in the proposed antenna, a wide slot is introduced in the square ground plane and the rectangular patch is shifted toward the left edge of the ground surface. In addition, by means of introducing square-shaped stubs near the left and right edge of the ground plane, the circular polarization is achieved at L1, L2, and L5 satellite bands. As per the simulation results, the proposed antenna provides a wide impedance bandwidth (S11&lt;−10 dB) of 123% (1.12–4.72 GHz) and 3 dB axial ratio bandwidth of 11% (1.15–1.29 GHz) and 18% (1.5–1.8 GHz) suitable for multipurpose wireless applications. The designed single feed circularly polarized antenna is low profile, small size, light weight and easily integrable with other high-frequency communication devices. To validate radiation performance of the proposed structure, the antenna is fabricated and integrated with the commercially available Global Positioning System (GPS) receiver and it is found that the measured values are in close agreement with the desired results.


Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Preet Kaur ◽  
Pravin R. Prajapati

Abstract A bilayer split-ring chiral metamaterial converts the linearly polarized wave, into a nearly perfect left or right-handed circularly polarized wave. The proposed antenna is intended to operate at center frequency of 5.80 GHz with switchable polarization capability. The polarization re-configurability is achieved by electronically switching of two PIN-diode pairs, which are embedded into bilayer split-ring Chiral Metamaterial. The optimized length of rectangular patch is 16 mm and width is 12.1 mm. Two types of radiation characteristics offered by the proposed antenna; left hand circularly polarized in mode 1 and right hand circularly polarized in mode 2. Measured results show that its impedance bandwidth is 155 MHz from 5.70 to 5.855 GHz for both mode 1 and mode 2. The measured axial-ratio bandwidth is 100 MHz from 5.75 to 5.85 GHz for mode 1 and 110 MHz from 5.73 to 5.84 GHz for mode 2. Antenna has LHCP gain of 2.52 dBi and RHCP gain of −23 dBi in mode 1. RHCP gain of 2 dBi and polarization purity of about −20 dBi is obtained in mode 2. The proposed antenna has simple structure, low cost and it has potential application in field of wireless communication (i.e., WiMax, WLAN etc.).


Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 651-655 ◽  
Author(s):  
Yilin Liu ◽  
Kama Huang

Abstract A novel design of a coplanar waveguide (CPW) feed antenna array with circular polarization (CP) and a high front-to-back ratio is described. The proposed CP array is achieved by using a compact CPW–slotline transition network etched in the ground plane. The measured results show that this kind of feeding method can improve the impedance bandwidth, as well as the axial ratio bandwidth of the CP antenna array and provide adequate gain. The proposed array can achieve a 6.08% impedance bandwidth and a 4.10% CP bandwidth. Details of the antenna design and experimental results are presented and discussed.


Author(s):  
Sonal Gupta ◽  
Shilpee Patil ◽  
Chhaya Dalela ◽  
Binod Kumar Kanaujia

Abstract Design of single-feed circularly polarized (CP) microstrip antenna is proposed in this article. The design employs the concept of E-shape patch with inclined fractal defected ground structure (IFDGS), which can improve the impedance bandwidth, gain, and axial ratio (AR) bandwidth. The excellent enhanced impedance bandwidth, axial ratio bandwidth, and gain are achieved by an inclined E-shaped fractal etched on the ground plane. The parameter studies of the E-shaped IFDGS are given to illustrate the way to obtain CP radiation. The third iterative IFDGS is fabricated on easily available FR4 substrate with a size of 0.494 λ0 × 0.494 λ0 × 0.019 λ0 (λ0 is the wavelength in free space at 3.624 GHz). The measured results verify the simulated results and show good agreement. The proposed antenna shows an impedance bandwidth of 12.7% at a centre frequency of 3.47 GHz and 3-dB AR bandwidth for this band is 2.39% at a centre frequency of 3.626 GHz. The measured peak gain for the proposed antenna is found as 8.1 dBi. The proposed antenna can be suitable for mobile WIMAX operation (IEEE 802.16e-2005 standard), wireless communication in CA-band and FCC.


2018 ◽  
Vol 11 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Gunjan Srivastava

A compact circularly polarized antenna with wide axial ratio bandwidth (ARBW) using quasi-self-complementary (QSC) structure is presented. A 3-dB ARBW is achieved by shortening the ground plane of the QSC structure. Furthermore, the wide ARBW is obtained by the introduction of a stepped stub in the extended ground plane of the QSC structure. The antenna is fabricated on a FR4 substrate with the overall dimensions of 25 mm × 22 mm × 0.8 mm. The proposed antenna has an impedance bandwidth of 5.9 GHz (2.4–8.3 GHz, 110%) and 3 dB ARBW of 1.6 GHz (2.4–4 GHz, 50%). A peak gain of 1–3 dBi is observed within the 3 dB ARBW.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Ke Zhang ◽  
Changrong Liu ◽  
Xueguan Liu ◽  
Huiping Guo ◽  
Xinmi Yang

A compact circularly polarized antenna operating at 915 MHz industrial, scientific, and medical (ISM) band for biomedical implantable applications is presented and experimentally measured. The proposed antenna can be miniaturized to a large extent with the compact size of 15 × 15 × 1.27 mm3 by means of loading patches to a ring-shaped microstrip patch antenna. An impedance bandwidth of 10.6% (865–962 MHz) for reflection coefficient less than −10 dB can be obtained. Meanwhile, the simulated 3 dB axial-ratio (AR) bandwidth reaches 14 MHz. Finally, the optimized design was fabricated and tested, and the measured results agree well with simulated results.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wei He ◽  
Yejun He ◽  
Long Zhang ◽  
Sai-Wai Wong ◽  
Wenting Li ◽  
...  

In this paper, a low-profile circularly polarized (CP) conical-beam antenna with a wide overlap bandwidth is presented. Such an antenna is constructed on the two sides of a square substrate. The antenna consists of a wideband monopolar patch antenna fed by a probe in the center and two sets of arc-hook-shaped branches. The monopolar patch antenna is loaded by a set of conductive shorting vias to achieve a wideband vertically polarized electric field. Two sets of arc-hook-shaped parasitic branches connected to the patch and ground plane can generate a horizontally polarized electric field. To further increase the bandwidth of the horizontally polarized electric field, two types of arc-hook-shaped branches with different sizes are used, which can generate another resonant frequency. When the parameters of the arc-hook-shaped branches are reasonably adjusted, a 90° phase difference can be generated between the vertically polarized electric field and the horizontally polarized electric field, so that the antenna can produce a wideband CP radiation pattern with a conical beam. The proposed antenna has a wide impedance bandwidth ( ∣ S 11 ∣ < − 10   dB ) of 35.6% (4.97-7.14 GHz) and a 3 dB axial ratio (AR) bandwidth at phi = 0 ° and theta = 35 ° of about 30.1% (4.97-6.73 GHz). Compared with the earlier reported conical-beam CP antennas, an important feature of the proposed antenna is that the AR bandwidth is completely included in the impedance bandwidth, that is, the overlap bandwidth of ∣ S 11 ∣ < − 10   dB and AR < 3   dB is 30.1%. Moreover, the stable omnidirectional conical-beam radiation patterns can be maintained within the whole operational bandwidth.


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