scholarly journals Single-Arm Archimedean Spiral Antenna with Broadband Circular Polarization

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Qingyuan Fang ◽  
Mengzhe Jin ◽  
Weidong Liu

In this paper, a single-arm Archimedean spiral (SAAS) antenna with broadband circular polarization is investigated. Unlike traditional single-arm Archimedean spiral antenna, the antenna arm consists of a hybrid meandered strip line and a smooth arc strip line. Especially at low frequencies, the meandered strip line significantly improves the circular polarization performance by extending the antenna surface current path. The effects of the meandered strip line on the radiation pattern and axial ratio (AR) are studied in detail. To obtain unidirectional radiation, a metallic cavity is added below the SAAS antenna. The measurement results show that the voltage standing wave ratio (VSWR) is less than 2 from 0.88 GHz to 8.82 GHz, which indicates a wide impedance bandwidth of 1 : 10 is realized. A wide AR bandwidth of 1 : 5 is available, that the measured AR is less than 3 dB from 1.6 GHz to 8 GHz.

2019 ◽  
Vol 12 (2) ◽  
pp. 176-182 ◽  
Author(s):  
Amer T. Abed ◽  
Mandeep S. J. Singh ◽  
Aqeel M. Jawad

AbstractThis paper describes and analyzes a new technique used in Q-slot antenna to generate circular polarization (CP). The CP characteristics were investigated carefully by studying the surface current distribution, the phase difference between the left hand circular polarization (LHCP) and right hand circular polarization (RHCP) at some resonant frequencies, and the measured values of the axial ratio bandwidth (ARBW). Normal arms (E1 and E2) were cut in the upper elliptical feeding strip line to form an open-mouth structure. The arms E1 and E2 were made equal in length and set perpendicular to each other to have normal electric fields, leading to the generation of CP radiation. A formula was modified for the dual resonant frequencies f1, f2 of the modes TM010 and TM001. The measured values of the ARBW indicated that the antenna has a wide ARBW of 4.8–5.93 GHz, which is approximately 52% of the 3rd operating band of 4.7–6.8 GHz. The wide ARBW in a small size indicated that the design of the Q-slot antenna overcame the limits of designing antennas with wide ARBW in small size and low profile. A formula for normalized field was driven according to the complementary of the Q-slot antenna.


Frequenz ◽  
2019 ◽  
Vol 73 (5-6) ◽  
pp. 153-159
Author(s):  
Zhuo Mu ◽  
Shen-Yun Wang ◽  
Wen-Ying Meng

Abstract This paper reports a novel polarization-reconfigurable antenna array based on the theory of mode combination (MC), which can electronically alter its polarization states between left-hand circular polarization (LCP) mode, right-hand circular polarization (RCP) mode, and two combined linear polarization (LP) modes. The array element is adopted as the L-probes fed circularly-polarized antenna reported by Luk et al. [1]. To verify the concept, a prototype of 2×2 antenna array is manufactured and tested. By properly exciting the feeding probes, four polarization modes can be switchable. Measurement results show that the proposed antenna has an overlapped −10 dB impedance bandwidth around 34 % for both CP modes and LP(2) mode, and an overlapped 3 dB axial-ratio bandwidth around 22.0 % of the CP modes. The average realized gains are around 12.4 dB for CP modes and LP(1) mode, which remain stable in the axial-ratio bandwidth.


Frequenz ◽  
2020 ◽  
Vol 74 (5-6) ◽  
pp. 191-199
Author(s):  
M. K. Verma ◽  
Binod K. Kanaujia ◽  
J. P. Saini ◽  
Padam S. Saini

AbstractA broadband circularly polarized slotted square patch antenna with horizontal meandered strip (HMS) is presented and studied. The HMS feeding technique provides the good impedance matching and broadside symmetrical radiation patterns. A set of cross asymmetrical slots are etched on the radiating patch to realize the circular polarization. An electrically small stub is added on the edge of the antenna for further improvement in performance. Measured 10-dB impedance bandwidth (IBW) and 3-dB axial ratio bandwidth (ARBW) of the proposed antenna are 32.31 % (3.14–4.35 GHz) and 20.91 % (3.34–4.12 GHz), respectively. The gain of the antenna is varied from 3.5 to 4.86dBi within 3-dB ARBW. Measured results matched well with the simulated results.


Author(s):  
Alaa Imran AL-Muttairi ◽  
Malik Jasim Farhan

In this paper, a novel low cost, single-feed, and circular polarization reconfigurable antenna is designed and fabricated for future mid-band 5G applications. An innovative technique is used in this approach, which combines three techniques, namely: polygon U-slot, switchable vertical or horizontal slots, and shorting posts. The proposed antenna can alter its polarization sense between RHCP and LHCP with the ability to adjust the axial ratio position with respect to frequency along the impedance bandwidth of the antenna. The antenna is built on RT/duroid 5880 substrate with a maximum size of (31*31*3.15) .Two real diodes are integrated across the slot to change polarization sense. CST commercial software is used to simulate the antenna, and then it is fabricated and measured practically. Good agreements between the two results are achieved. However, The antenna has impedance bandwidth starting from 3.4995GHz to 3.73GHz with overlapped axial ratio bandwidth of 2.1% for both operation senses. Also, the antenna has good gain, and it has one resonant frequency at 3.6GHz for both operating states.


2016 ◽  
Vol 78 (5-9) ◽  
Author(s):  
Muhammad Fauzan Edy Purnomo ◽  
Hadi Suyono ◽  
Panca Mudjirahardjo ◽  
Rini Nur Hasanah

The circularly polarized (CP) microstrip antennas, both of singly- and doubly-fed types, possess inherent limitation in gain, impedance and axial-ratio bandwidths. These limitations are caused mainly by the natural resonance of the patch antenna which has a high unloaded Q-factor and the frequency-dependent excitation of two degenerative modes (TM01 and TM10) when using a single feed. Many applications which require circular polarization, large bandwidth, and good performance, especially in the field of wireless communication, are still difficult to be designed by using antenna software. Some consideration to take will include the application target and design specification, the materials to be used, and the method to choose (formula, numerical analysis, etc). This paper explains and analyzes the singly-fed microstrip antenna with circular polarization and large bandwidth. This singly-fed type of microstrip antenna provides certain advantage of requiring no external circular polarizer, e.g. the 900 hybrid, as it only needs to apply some perturbation or modification to a patch radiator with a standard geometry. The design of CP and large-bandwidth microstrip antenna is done gradually, by firstly truncating one tip, then truncating the whole three tips, and finally modifying it into a pentagonal patch structure and adding an air-gap to obtain larger bandwidths of impedance, gain and axial ratio. The last one antenna structure results in a novelty because it is a rare design of antenna which includes all types of bandwidth (impedance, gain, and axial ratio) being simultaneously larger than the origin antenna. The resulted characteristic performance of the 1-tip (one-tip) antenna shows respectively 1.9% of impedance bandwidth, 3.1% of gain bandwidth, and 0.45% of axial-ratio bandwidth. For the 3-tip (three-tip) step, the resulted bandwidths of respectively impedance, gain, and axial ratio are 1.7%, 3.3% and 0.5%. The pentagonal structure resulted in the bandwith values of 15.67%, 52.16% and 4.11% respectively for impedance, gain, and axial ratio. 


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Sitthichai Dentri ◽  
Khanet Pookkapund ◽  
Bancha Luadang ◽  
Prayoot Akkaraekthalin ◽  
Chuwong Phongcharoenpanich

This research proposes a single-fed broadband circularly polarized (CP) bidirectional antenna operable in 840–960 MHz frequency band for readers of universal UHF-RFID applications. The proposed antenna is comprised of upper-layer conductor, lower-layer conductor, and wall patches. The upper-layer conductor consists of two diagonally aligned rectangular copper plates with a feeding gap at the center, and the lower-layer conductor is of two diagonally adjoined rectangular plates. The upper- and lower-layer conductors are adjoined with the wall patches. The diagonal alignment technique of the upper- and lower-layer plates was used to realize circular polarization and improve 3-dB axial ratio (AR) bandwidth. The double layers were deployed to improve impedance bandwidth (|S11| < −10 dB) and achieve bidirectional radiation pattern. The simulated impedance bandwidth and 3-dB AR bandwidth were 772.19–1014.6 MHz (27.13%) and 675–1000 MHz (38.80%), and the corresponding measured results were 759–1011 MHz (28.47%) and 648–1110 MHz (52.55%). The simulated LHCP/RHCP half-power beamwidth (HPBW), 3-dB AR beamwidth, and gain were 56° – 90°/54° – 92°, 60° – 104°, and 4.94 – 5.89 dBic, while the corresponding measured results were 52° – 98°/62° – 97°, 96° – 126°, and 4.28 – 5.72 dBic. As a result, the single-fed broadband CP bidirectional antenna is applicable to universal UHF-RFID readers. Besides, the novelty of this research lies in the use of diagonal alignment of conducting plates to achieve circular polarization and wider AR bandwidth.


2014 ◽  
Vol 631-632 ◽  
pp. 306-309
Author(s):  
Chun Hui Mou ◽  
Tao Hong ◽  
Wen Jiang ◽  
Shu Xi Gong

An ultra-wideband (UWB) circularly polarized complex spiral antenna with low radar cross section (RCS) is proposed in this paper. By replacing the metal reflect board of the antenna with a novel UWB frequency selective surface (FSS), the RCS of the spiral antenna is significantly reduced in a wide frequency range, while the radiation performances of the spiral antenna are maintained. The proposed antenna operates over the frequency band between 2GHz to 6.5GHz under the condition of axial ratio<3dB and |S11| < - 10dB. Simulation and measurement results demonstrate the validation of broadband spiral antenna RCS reduction by using the novel UWB FSS.


2016 ◽  
Vol 9 (4) ◽  
pp. 843-850 ◽  
Author(s):  
Dinesh Kumar Singh ◽  
Binod Kumar Kanaujia ◽  
Santanu Dwari ◽  
Ganga Prasad Pandey ◽  
Sandeep Kumar

The design and measurement of reconfigurable circularly polarized capacitive fed microstrip antenna are presented. Small isosceles right angle triangular sections are removed from diagonally opposite corners for the generation of circular polarization (CP) of axial ratio bandwidth of 11.1%. Horizontal slits of different lengths are inserted at the edges of the truncated patch to provide the dual-band CP and by switching PIN diodes across the slits ON and OFF, reconfigurable circularly polarized antenna is realized. The antenna shows dual-band behavior with reconfigurable CP. In order to enhance the operation bandwidth of the antenna, an inclined slot was embedded on the patch along with PIN diodes across the horizontal slits. This proposed antenna gave an impedance bandwidth of 66.61% (ON state) ranging from 4.42 to 8.80 GHz and 68.42% (OFF state) ranging from 4.12 to 8.91 GHz and exhibits dual-frequency CP with PIN diode in OFF state and single-frequency CP with PIN diode in ON state with good axial ratio bandwidth. The axial ratio bandwidth of 4.42, 2.35, and 2.72% is obtained from the antenna. The antenna has a similar radiation pattern in all the three different CP bands and almost constant gain within the bands of CP operation.


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