scholarly journals A Miniaturized Circularly-Polarized Antenna for In-Body Wireless Communications

Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 70 ◽  
Author(s):  
Yi Fan ◽  
Xiongying Liu ◽  
Jiming Li ◽  
Tianhai Chang

A novel miniaturized single-fed circularly-polarized (CP) microstrip patch antenna operating in the Industrial, Scientific, Medical (ISM) band of 2.40–2.48 GHz, is comprehensively proposed for implantable wireless communications. By employing reactive loading in the arrow-shaped slotted patch to form slow wave effect and embedding V-shaped slots into patch to lengthen the current path, the proposed implantable antenna is minimized with the overall dimensions of 9.2 mm × 9.2 mm × 1.27 mm. The radiation patterns of the proposed antenna illustrate the performance of left-handed circular polarization. The simulated results show that an impedance bandwidth of 7.2% (2.39–2.57 GHz) and an axial ratio bandwidth of 3.7% (2.39–2.48 GHz) at the ISM band are achieved, respectively. Ex vivo measured results are in good agreement with the corresponding simulated ones.

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.


Frequenz ◽  
2019 ◽  
Vol 73 (9-10) ◽  
pp. 317-320
Author(s):  
Saeid Karamzadeh ◽  
Vahid Rafiei ◽  
Hasan Saygin

Abstract In this work circularly polarization diversity has been achieved by utilizing two Schottky diodes on low profile cavity-backed substrate integrated waveguide (CBSIW). In comparison with other studies in the literature, the size of antenna has been reduced to 0.54λg × 0.76λg by helping a 50-Ohm coaxial feed line. The impedance bandwidth, axial ratio bandwidth and antenna gain are improved to 10.02 %, 5.2 % and 7.68dBi, respectively. In addition, the proposed antenna can generate either a left-hand circularly polarized (LHCP) or a right-hand circularly polarized (RHCP) radiation. The developed antenna was fabricated and tested and the achieved results were in good agreement with the simulated one.


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.


2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Deqiang Yang ◽  
Meng Zou ◽  
Jin Pan

A single-point-fed circularly polarized (CP) rectangular dielectric resonator antenna (DRA) with wide CP bandwidth is presented. By usingTE111andTE113modes of the rectangular DRA, a wideband CP performance is achieved. The coupling slot of the antenna contains a resistor loaded monofilar-spiral-slot and four linear slots. Design concept of the proposed antenna is demonstrated by simulations, and parameter studies are carried out. Prototype of the proposed antenna was fabricated and measured. Good agreement between the simulation and measurement is obtained. The measured impedance bandwidth (|S11|<-10 dB) and 3 dB axial-ratio (AR) bandwidth are 51.4% (1.91–3.23 GHz) and 33.0% (2.15–3.00 GHz), respectively.


Author(s):  
Amrita Gorai ◽  
Bappadittya Roy ◽  
G. K. Mahanti

A compact circularly polarized CPW-fed slot antenna is proposed here. The antenna consists of a pentagonal patch within an asymmetrical slot with a single coplanar waveguide feed. The proposed antenna is excited with CPW feed mechanism and investigated experimentally. The structure is fabricated on FR4 epoxy substrate with a permittivity of 4.4. The impedance bandwidth of 10[Formula: see text]GHz (4[Formula: see text]GHz to 14[Formula: see text]GHz) and the axial ratio bandwidth of 1.2[Formula: see text]GHz with the corresponding fractional bandwidth of 113%. The simulation results fulfil the bandwidth requirements of IEEE 802.11a (5.15–5.35[Formula: see text]GHz/5.47–5.725[Formula: see text]GHz) for wireless applications. In terms of bandwidth, compactness and circular polarization comparable results between simulated and measured results clearly show the validity of the proposed structure.


2019 ◽  
Vol 12 (3) ◽  
pp. 212-220 ◽  
Author(s):  
Alka Verma ◽  
Anil Kumar Singh ◽  
Neelam Srivastava ◽  
Shilpee Patil ◽  
Binod Kumar Kanaujia

AbstractIn this paper, an electromagnetic band gap (EBG) metasurface (MS) superstrate-based circularly polarized antenna for the WiMAX (3.5 GHz) band is proposed. The proposed structure comprises a 2 × 2 slot-loaded rectangular patch MS array that can be perceived as a polarization-dependent EBG MS superstrate. Furthermore, to achieve circular polarization, the proposed antenna has an inclined coupling slot onto the ground with a conventional coplanar waveguide feed line. The proposed antenna has a compact structure with a low profile of 0.037λ0 (λ0 stands for the free-space wavelength at 3.48 GHz) and a ground size of 30 × 30 mm2. The measured results show that the −10 dB impedance bandwidth for the proposed antenna is 34.6% and the 3-dB axial ratio (AR) bandwidth is 6.8% with a peak gain of 3.91 dBi in the desired operating band. Good agreement between the simulated and the measured results verifies the performance of the proposed antenna.


Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 121
Author(s):  
Chao Xu ◽  
Yi Fan ◽  
Xiongying Liu

A circularly polarized implantable antenna integrated with a voltage-doubled rectifier (abbr., rectenna) is investigated for microwave wireless power transfer in the industrial, scientific, and medical (ISM) band of 2.4–2.48 GHz. The proposed antenna is miniaturized with the dimensions of 7.5 mm × 7.5 mm × 1.27 mm by etching four C-shaped open slots on the patch. A rectangular slot truncated diagonally is cut to improve the circular polarization performance of the antenna. The simulated impedance bandwidth in a three-layer phantom is 30.4% (1.9–2.58 GHz) with |S11| below −10 dB, and the 3-dB axial-ratio bandwidth is 16.9% (2.17–2.57 GHz). Furthermore, a voltage-doubled rectifier circuit that converts RF power to DC power is designed on the back of the antenna. The simulated RF-to-DC conversion efficiency can be up to 45% at the input power of 0 dBm. The proposed rectenna was fabricated and measured in fresh pork to verify the simulated results and evaluate the performance of wireless power transfer.


2020 ◽  
Vol 9 (1) ◽  
pp. 41-48
Author(s):  
P. M. Paul ◽  
K. Kandasamy ◽  
M. S. Sharawi

A compact multiband circularly polarized slot antenna is proposed here. An F-shaped microstrip feedline is used to excite the square slot antenna loaded with a U-shaped strip and a split ring resonator (SRR) to generate three circularly polarized bands at 1.5 GHz, 2.75 GHz and 3.16 GHz. A meandered slot is used in the feedline and the U-strip to improve the axial ratio bandwidth (ARBW). The meandered feedline excites the slot to produce resonance at 2.5 GHz. This resonance along with that of the F-shaped feed, loaded SRR and U-strip combine to give rise to three circularly polarized bands which can be tuned depending on the feed, SRR and U-strip dimensions. The orientation of the F-shaped feed decides the sense of polarization of the three circularly polarized bands of the proposed antenna. The proposed antenna is fabricated on a substrate of FR4 material with dimensions 50 x 50 x 1.56 mm3. The antenna is prototyped and measured in terms of impedance bandwidth, ARBW, gain and efficiency. The simulated and measured results show reasonably good agreement.


2021 ◽  
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.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Sorana Niyamanon ◽  
Rewat Senathong ◽  
Chuwong Phongcharoenpanich

This research proposes a dual-frequency circularly polarized truncated square aperture patch antenna with slant stripline and L-shaped slot for WLAN applications. In the antenna design, the parameters were optimized and the WLAN-enabled dual-frequency (2.4 and 5.8 GHz) antenna was realized. Simulations were subsequently carried out for the impedance bandwidth (S11) < −10 dB, axial ratio (AR) ≤ 3 dB, optimal gain, and bidirectional radiation pattern. To validate, an antenna prototype was fabricated and the experiments were undertaken. The simulated and experimental results are in good agreement. In essence, the proposed WLAN-enabled dual-frequency circularly polarized antenna is most suited for applications in the vertically and horizontally elongated areas, including in the tunnel, train carriage, and buildings.


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