scholarly journals A Novel Compact CP Antenna with Wide Axial Ratio Bandwidth for Worldwide UHF RFID Handheld Reader

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Waleed Abdelrahim Ahmed ◽  
Feng Quanyuan

This study presents a novel compact circularly polarized antenna for universal ultrahigh-frequency (UHF) radio-frequency identification (RFID) handheld reader applications. The antenna is composed of a coplanar waveguide (CPW) L-shaped feedline mounted at the right edge of the square slot at the bottom of the ground plane to realize a circular polarization; a horizontal stub protruded from the right side of the square slot towards the slot centre, and a vertical stub is mounted at the lower left of the square slot. The designed antenna printed on one ground plane layer of a low-cost FR4 substrate with an overall size of 120×120×1.6 mm3. The measurement results show indicate that the fabricated antenna achieves a wide axial ratio (AR) bandwidth of 460 MHz (818–1278 MHz), wide impedance bandwidth of 54.6% (630–1103 MHz), and a measured peak gain of 4.0 dBi. The proposed antenna is a good candidate for compact universal UHF RFID handheld reader applications (840–960 MHz).

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Sun-Woong Kim ◽  
Guen-Sik Kim ◽  
Dong-You Choi

We propose a wide bandwidth antenna with a circular polarization for universal Ultra High Frequency (UHF) radio-frequency identification (RFID) reader applications. To achieve a wide 3 dB axial ratio (AR) bandwidth, three T-shaped microstrip lines are inserted into the ground plane. The measured impedance bandwidth of the proposed antenna is 480 MHz and extends from 660 to 1080 MHz, and the 3 dB AR bandwidth is 350 MHz and extends from 800 to 1155 MHz. The radiation pattern is a bidirectional pattern with a maximum antenna gain of 3.67 dBi. The overall size of the proposed antenna is 114 × 114 × 0.8 mm3.


2018 ◽  
Vol 7 (5) ◽  
pp. 94-100 ◽  
Author(s):  
S. Pandey ◽  
G. P. Pandey ◽  
P. M. Sarum

A compact, square shaped microstrip fractal antenna with asymmetrical pairs of T-slits for circularly polarized (CP) radiation and radio frequency identification (RFID) reader applications is proposed and experimentally investigated. Design is based on narrow slit modified Minkowski island fractal geometry. Circular polarization along with size reduction is achieved by inserting four symmetrical pairs of T-slits at the square patch boundary of the single-probe-feed radiator. Proposed geometry is tuned at resonant frequency of 914 MHz by optimization of dimensions of the two T-slits. Compactness of the antenna is achieved by increasing the overall sizes of the slits. Antenna is fabricated on FR4 substrate with a size of 47.2×47.2×1.6 mm3 (0.143λ0 X 0.143λ0 X 0.005λ0) and tested to validate the simulated results. The 3-dB axial-ratio (AR) bandwidth and impedance bandwidth of the proposed antenna design are found to be 7 MHz (911-918 MHz) and 24 MHz (909-933 MHz) respectively. A design equation is develped based on the parametric study that can be used to design a compact antenna with CP for UHF RFID applications covering the frequency range from 887 to 1023 MHz.


2021 ◽  
Vol 36 (6) ◽  
pp. 747-754
Author(s):  
Rui Ma ◽  
Quanyuan Feng

This paper presents a new coplanar waveguide (CPW)-fed circularly polarized square slot antenna (CPSSA). The proposed antenna uses an inverted Z-shaped feedline protruded from the signal line of the feeding CPW. Circularly polarized (CP) radiation can be achieved by adequately inserting the arc-shaped grounded strip into the upper right corner of the square slot. The widened vertical tuning stub on the L-shaped grounded strip can improve impedance matching and axial ratio (AR) performance. The measured results indicate that the 10 dB impedance bandwidth is 620 MHz (652-1272 MHz), and the 3 dB axial ratio bandwidth is 320 MHz (840-1160 MHz), which has a broadband characteristic. In the range of the universal UHF RFID band, the measured peak gain is about 4.4 dBi. The proposed CPSSA uses low-cost FR4 material as the dielectric substrate. The overall size of the antenna is 119 × 119 × 0.5 mm3. The proposed antenna has a simple structure, easy processing, good performance, wide operating bandwidth, and dual circular polarization characteristic. It can be applied to the universal UHF RFID handheld reader environment.


Frequenz ◽  
2018 ◽  
Vol 72 (5-6) ◽  
pp. 181-188
Author(s):  
Chien-Yuan Pan ◽  
Chum-Chieh Su ◽  
Wei-Lin Yang

Abstract A new circularly polarized (CP) slot antenna with a small gap and a stick-shaped shorted strip is presented. The proposed antenna has a sufficient bandwidth for ultrahigh frequency (UHF) radio-frequency identification (RFID) reader applications. The antenna structure consists of a rectangular slot with a small gap, a stick-shaped shorted strip and a 50 Ω coplanar waveguide (CPW) feedline with an asymmetrical ground plane. By using the stick -shaped shorted strip to disturb magnetic current distribution on the slot, the CP radiation can be generated. The measured results demonstrate that the proposed antenna can reach a 10 dB return loss impedance bandwidth of 14.1 % (894–1030 MHz) and a 3 dB axial ratio (AR) bandwidth of 6.4 % (910–970 MHz). The whole antenna size is 80 × 80 × 1.6 mm3.


2021 ◽  
Vol 17 (1) ◽  
pp. 1-11
Author(s):  
Vijay Sharma ◽  
Tejpal Jhajharia

Abstract The article proposes design investigation and experimental results of a coplanar waveguide (CPW) fed square slot antenna that gives wideband circular polarization. This circular polarization characteristic is achieved by embedding a square shape stub to left bottom corner and an L-shaped strip to the right upper corner of the slot. A high impedance bandwidth of 87.8 % (3.6–9.0 GHz), a wide axial ratio bandwidth of 73.05 % (4.2–9.0 GHz) and wide 3-dB axial ratio beamwidth of 90° in the entire frequency range of interest are achieved with this antenna structure. To improve the 3-dB axial ratio bandwidth, three slots (two horizontal and one vertical) are scratched at the exterior periphery of the ground plane. These perturbation assemblies are accountable to excite orthogonal modes and help increase an axial ratio bandwidth. The designed antenna displays the constant and steady radiation patterns in the complete frequency range of concern. The overall dimension of the presented compact antenna is 0.24λ × 0.24λ × 0.01λ.


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.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Bin You ◽  
Bo Yang ◽  
Xuan Wen ◽  
Liangyu Qu

A new ultrahigh frequency radio frequency identification (UHF RFID) reader’s front-end circuit which is based on zero-IF, single antenna structure and composed of discrete components has been designed. The proposed design brings a significant improvement of the reading performance by adopting a carrier leakage suppression (CLS) circuit instead of a circulator which is utilized by most of the conventional RF front-end circuit. Experimental results show that the proposed design improves both the sensitivity and detection range compared to the conventional designs.


Author(s):  
Ibtissame Bouhassoune ◽  
Abdellah Chehri ◽  
Rachid Saadane ◽  
Khalid Minaoui

In this paper, a new flexible wearable radio frequency identification (RFID) five-shaped slot patch tag placed on the human arm is designed for ultra-high frequency (UHF) healthcare sensing applications. The compact proposed tag consists of a patch structure provided with five shaped slot radiators and a flexible substrate, which minimize the human body’s impact on the antenna radiation performance. We have optimized our designed tag using the particle swarm optimization (PSO) method with curve fitting within MATLAB to minimize antenna parameters to achieve a good return loss and an attractive radiation performance in the operating band. The PSO-optimized tag’s performance has been examined over the specific placement in some parts of the human body, such as wrist and chest, to evaluate the tag response and enable our tag antenna conception in wearable biomedical sensing applications. Finally, we have tested the robustness of this tag by evaluating its sensitivity as a function of the antenna radiator placement over the ground plane or by shaping the ground plane substrate for the tag’s position from the human body. Our numerical results show an optimal tag size with good matching features and promising read ranges near the human body.


A wideband coplanar waveguide (CPW) antenna with circular polarization characteristics using modified ground slot is studied in this work. Proposed design incorporates a hexagonal slot instead of rectangular slot, accounting for enhanced impedance matching. This ground slot is energized by a 50Ω feed line, resulting in excitation of two orthogonal phase quadrature modes (even-odd modes). Thus, fulfilling the essential criteria required for realizing circular polarization. A narrow horizontal slit (lg) is embedded in the ground plane at immediate left of feed line, accounting for wideband characteristics. 10dB impedance bandwidth of proposed antenna extends from 2.65- 5.60 GHz, while 3dB axial ratio bandwidth extends from 3.90- 5.80 GHz. Hence, overlapping bandwidth of proposed antenna extends from 3.90 - 5.60 GHz. RHCP characteristics with monopole radiation pattern makes proposed antenna useful for WLAN, radio navigation and radiolocation applications.


2016 ◽  
Vol 20 (1) ◽  
pp. 22
Author(s):  
Jianxiong Li ◽  
Shanlin Song ◽  
Xiaoyu Chen ◽  
Hua Nian ◽  
Weiguang Shi

The directional coupler is applied to isolating RX from TX because of low cost and simplicity compared to the circulator in the radio-frequency identification (RFID) reader. Because of unequal phase velocity between odd and even mode, the drawback of the traditional microstrip directional coupler is poor isolation. In this paper, to obtain a good isolation between RX and TX, a novel directional coupler is proposed to be applied to the UHF RFID system with a single antenna. Measurement result shows that the proposed directional coupler possesses a good isolation of -35dB in operating frequency band.


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