Circularly Polarized Antenna Array Research Articles

Compact Series-fed Circularly-polarized Patch Array basedon Microstrip Line

A compact single-layer circularly polarized (CP) antenna array is proposed in this paper for 5G/6G applications. The conventional microstrip line is modified as a feeding network by periodically and alternatively loading field blocking stubs, producing a linearly polarized in-phase radiative field aperture. By adding CP corner-truncated patches beside these in-phase fields, a linear high-gain CP antenna array excited by a single feed is obtained. The feasibility of the proposed design is demonstrated through the fabrication and measurement of a 16-element linear array. The results indicate that the 3 dB axial ratio bandwidth is 3.5% (19.60∼20.30 GHz), the -10 dB impedance bandwidth totally covers the 3 dB axial ratio bandwidth, and the peak realized gain is 14.9 dBi under an antenna length of 5.69λ0. This proposed strategy provides a very compact antenna structure to achieve high-gain CP radiation without the requirement of impedance transformers, phase shifters, and open-stop-band suppressing measures. Moreover, the antenna has a per-unit-length CP gain of 5.5/λ0, which is superior to many single-layer high-gain CPantennas.

A Wideband Circularly Polarized Antenna Array Loaded with Dual-Layer Metasurface

A Wideband Circularly Polarized Antenna Array Loaded with Dual-Layer Metasurface

The Design of a Circularly Polarized Antenna Array with Flat-Top Beam for an Electronic Toll Collection System

The Design of a Circularly Polarized Antenna Array with Flat-Top Beam for an Electronic Toll Collection System

A Compact Single-Layer High-Gain Omnidirectional-Like Circularly Polarized Array Antenna Based on Complementary Source Radiation

A Compact Single-Layer High-Gain Omnidirectional-Like Circularly Polarized Array Antenna Based on Complementary Source Radiation

Wideband Circularly Polarized Antenna Array Using Three-Layer Segmented Patches for Q-Band Application

A compact wideband circularly polarized (CP) millimeter-wave (mm-wave) antenna array using three-layer segmented patches (SEP) element is presented in this letter. To achieve miniaturization and wideband feature, three-layer SEP with four <i>L</i>-shaped branches are first designed to generate three CP modes (AR minimum points) within a compact size. With the three CP modes, a broad AR bandwidth of 31.7&#x0025; is achieved by the proposed CP element. Then, four metallic vias and an <i>L</i>-shaped feeding line are used to improve impedance matching. As a result, a wide impedance bandwidth of 33.1&#x0025; is also obtained by the proposed CP element. Based on the proposed wideband CP element, a compact 4&#x00D7;4 CP antenna array fed by a simple full-incorporate microstrip network is designed. Measured results of the array show a 3 dB AR bandwidth of 29.7&#x0025; from 30.1-40.6 GHz, an impedance bandwidth of 36.1&#x0025; from 29.15-42.0 GHz, and a peak gain of 18.2 dBic, which is well suited for Q-band satellite communications.

Ka-band flat panel circularly polarized antenna array for LEO satellite communication systems

In this paper, a high gain circularly-polarized antenna array with a flat panel structure for low Earth orbit (LEO) satellite communication systems is proposed. This new CP structure can efficiently achieve high directivity and can easily be integrated with beamforming ICs (BFIC) when designing an antenna module, resulting in a good candidate for Ka-band satellite communications. Furthermore, the proposed FPAA can easily be extended to a larger scale array from a base unit in a 2 × 2 sub-array structure. Each sub-array is configured by four high-gain planar segmented antenna (PSA) elements with a sequentially rotating arrangement, where a single 4-channel BFIC can drive CP radiation. Unlike previously reported PSA elements that have limited CP performance, the proposed PSA-CP configuration adopts additional conductors and ground-via structures to further improve the CP gain, axial-ratio (AR), and cross-polarization (XPD) characteristics. To verify the performance of the proposed PSA-CP, a 2 × 2 left-hand circular polarization (LHCP) sub-array was fabricated at 28 GHz and tested with a BFIC. The measured 10-dB impedance and 3-dB AR bandwidths of the proposed 2 × 2 array were 13.92% and 12.5%, respectively. In addition, the measured peak gain was 15.2 dBic at 28.5 GHz with an XPD level of less than 15 dB.

A compact ultra-wideband circularly polarized antenna array for vehicular communications

A compact ultra-wideband circularly polarized antenna array for vehicular communications

A Wideband and High-Gain Circularly Polarized Antenna Array for Radio-Frequency Energy Harvesting Applications

A wideband millimeter-wave (mmWave) circularly polarized (CP) complementary antenna array is proposed herein for radio-frequency energy harvesting (RFEH) applications. The element is constructed of a CP magneto-electric (ME)-dipole antenna and innovatively introduces the complementary source technique to improve the CP radiation performance. The detailed analyses are provided to elaborate the operating principles of the element. Simulated results for the element reveal an impedance bandwidth of 25.7%, a 3-dB axial ratio (AR) bandwidth of 24.8%, and a gain of 8.7 ± 1.6 dBic over the spectrum. The element shows the stable radiation pattern and wide AR/impedance overlapping bandwidth (33.87–43.15 GHz) for RFEH applications covering the 35-, 37-, and 39-GHz bands. To enhance the gain for practical applications, the element is employed in the design, fabrication, and testing of a planar <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times $ </tex-math></inline-formula> 4 array fed by a full-corporate substrate-integrated waveguide (SIW) network. Measured results indicate that the array achieves an impedance bandwidth of 20.2%, a 3-dB AR bandwidth of 24.3%, and a 3-dB gain bandwidth of 22.8%. Thus, the proposed array features a low profile and excellent performance, which makes it a desirable candidate for mmWave RFEH applications.

A Ku Wideband Circularly Polarized Microstrip Antenna Array with Low Profile Crossed-Dipole Element

This paper presents a novel Ku wideband circularly polarized (CP) antenna array composed of crossed-dipole element (CDE) and fed through sequential rotation (SR) feeding technique. Unlike the traditional CP-CDE fed by coaxial cable that usually works at low frequencies, the proposed CDE consists of two orthogonal heart-shaped patch dipoles that can work at frequencies as high as Ku-band, at the same time achieving a larger bandwidth. A feeding structure is proposed without welding, so potential errors in the antenna assembly process can be mitigated. A 2 × 2 CP antenna array with wideband SR feeding network is designed based on the CDE to further expand the axial ratio (AR) bandwidth. The designed antenna array is fabricated using the multilayer printed circuit board (PCB) technology and measured in anechoic chamber using the planar near-field measurement facility. The measured results show that −10 dB impedance bandwidth of 44% (11.6–18.15 GHz) along with 3 dB AR bandwidth of 38.7% (12–17.65 GHz) and 3 dB gain bandwidth of 34.6% (12.2–17.3 GHz) as well as 11.02 dBic peak gain have been achieved while maintaining a lower profile.

Wideband Circularly Polarized mm-Wave Array Antenna Using H-Shaped Low-Axial-Ratio Apertures

An H-shaped all-metal radiating element comprising an active and a coupled slot has been proposed to design wideband high-efficiency circularly-polarized antenna arrays. The proper excitation of several modes on the coupled slot enables a wide axial ratio bandwidth with high circular polarization purity. In order to feed an array of such radiating elements, a simple and scalable two-layer corporate network, implemented in groove gap waveguide technology, is conceived. Those good frequency properties have been confirmed by the fabrication of a prototype, whose experimental results report a 1-dB axial ratio bandwidth of 22%. In addition, a peak radiation efficiency of 97% with good pattern stability, and an impedance bandwidth of 21% with high return loss, have been measured. The high circular polarization purity demonstrated by these wideband apertures makes them particularly suitable for Ka-band satellite communications antennas.

A High-Gain Circularly Polarized Antenna Array Based on a Chiral Metastructure

In this article, a chiral metastructure absorber (CMMA) is combined with a circularly polarized (CP) antenna array based on a sequential-phase feed network, and the differential absorption of left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP) by CMMA unit is used to improve the axial ratio beamwidth (ARBW) of CP antenna array by absorbing the cross-polarization of the antenna array. The proposed CMMA unit achieves good circular dichroism at 4.9–5.2 GHz, which improves the ARBW of the antenna in this frequency band. In addition, the feed network of the antenna proposed in this article is in three-dimensional (3-D) form to reduce the coupling between the feed network and the radiation patches, so that higher gain can be obtained. The measured impedance bandwidth of the antenna is 80% (2.81–6.81 GHz), the axial ratio (AR) bandwidth is 70.8% (3.68–7.22 GHz), and the peak gain is 15.28 dBi.

Low-Cost Broadband Circularly Polarized Array Antenna with Artificial Magnetic Conductor for Indoor Applications

In this paper, we report a sequential-phase fed broadband circularly polarized array antenna loaded with an artificial magnetic conductor-reflecting surface. Our proposed antenna is a two-part group. The upper structure is a sequential-phase fed circular wide-slot antenna. The lower part is an artificial magnetic conductor structured reflective surface. The overall antenna size is 106 × 106 × 14.9 mm3, both adopting 1.6 mm thick FR4 material. The thickness of the air layer sandwiched between the antenna and the artificial magnetic conductor reflective surface is 14 mm. The antenna consists of four circular wide-slot antenna units with a sequential rotation technique. To broaden the axial ratio bandwidth, three L-shaped branches and four metal plates are attached to the circular wide-slot antenna unit and around the artificial magnetic conductor-reflecting surface, respectively. To verify the accuracy of the simulation, we fabricated the sample and then tested it in an anechoic chamber. The measured results demonstrate that the proposed broadband circularly polarized array antenna realizes an impedance bandwidth of 77.67% (2.74–6.22 GHz) and an axial ratio bandwidth of 65.16% (3.00–5.90 GHz) with a peak gain of 11.1 dBi. The design can be used in space-constrained environments, such as indoor and dense building areas.

Bandwidth-Enhanced Circularly Polarized Slot Antenna and Array Under Two Pairs of Degenerate Modes in a Single Resonant Cavity

A novel design concept of bandwidth-enhanced full-metal circularly polarized (CP) cavity-backed slot antenna and array based on two pairs of degenerate modes in a single cavity is proposed in this paper. Conventional CP antenna based on one pair of degenerate modes only has one axial-ratio (AR) minima and causes a narrow AR bandwidth. Two pairs of degenerate modes in a proposed multimode cavity resonator can initially produce two separate CP operating bands. Then, a pair of metal prisms is introduced to allocate the two bands in proximity to each other, thus obtaining a wide operating bandwidth with two AR minima. As the radiation slots are directly fed by the electric field of the cavity modes, 2 × 2 cross slots are placed on the top wall so as to comprise a CP array. As such, a very simple wideband CP antenna array is realized by virtue of a single multiple-mode resonator without needing extra power dividers. Finally, the 2 × 2 wideband CP antenna array is fabricated and measured. Measurement shows that the proposed antenna array can achieve 15% bandwidth, a peak gain of 11.8 dBic, and a peak total efficiency of 96%.

A HIGH GAIN CIRCULARLY POLARIZED (CP) ANTENNA ARRAY USING SEQUENTIAL PHASE (SP) ROTATION TECHNIQUE FOR WLAN APPLICATIONS

This paper designs and investigates a high gain circularly polarized 2 &amp;times; 2 antenna array for wireless applications using the sequential phase rotation technique. The feed network utilizes four rectangular lines of equal width and three 90&amp;deg; arcs. The length of all elements is equal to &amp;lambda;&lt;sub&gt;g&lt;/sub&gt;/4 to provide 0&amp;deg;, 90&amp;deg;, 180&amp;deg;, and 270&amp;deg; phase differences at the four outputs of feed network to increase the axial ratio(AR) bandwidth and purity. Four corner truncated patch elements are connected to the feed network to fulfill the 2 &amp;times; 2 antenna array design. The proposed design operates with an impedance bandwidth of 1.1 GHz from 4.9 GHz to 6 GHz bandwith and an AR bandwidth of 0.8 GHz from 5 GHz to 5.8 GHz band. The maximum measured gain of the antenna array is observed as 8.9 dBic in the operating band. The antenna array was prototyped and tested to validate its performance. This array is well suitable for high gain WLAN applications.

High-Gain Circularly Polarized Antenna Array for Full Incident Angle Coverage in RF Energy Harvesting

In this paper, a high-gain circularly polarized (CP) hexagonal antenna array is proposed for RF energy-harvesting applications. The hexagonal antenna array is intended to operate at the frequency of 5.8 GHz. It is composed of 6 multilayer substrate CP antennas excited by an X-shaped aperture-coupling feed structure. A frequency selective surface (FSS) was added to further improve the gain, resulting in a maximum gain of 12.7 dBi per element. The main advantage of the proposed hexagonal antenna array is the ability to cover 360 degrees in the azimuth plane with a high gain in all directions without the use of any additional circuitry, allowing the effective absorption of ambient RF energy. A prototype was fabricated and measured, and a good agreement with the simulation results is achieved. In addition, a rectifier is used to convert RF energy absorbed by the antenna into DC energy at the frequency of 5.8 GHz. The measured RF-to-DC conversion efficiency of 44.5% and a DC output voltage of 423 mV at -10 dBm are observed. The performance of the rectenna array with one and six rectifiers has been demonstrated. With the use of a DC combiner, the total RF to DC efficiency of the array is 67.75%, with a DC output voltage of 1.115 V from -10 dBm has been recorded. Due to the immunity to misalignment of the CP antenna, the proposed rectenna array is very suitable for wireless power transfer (WPT).

A Compact and Simply-Constructed All-Metal Circularly Polarized Ridge-Waveguide Slotted Antenna Array for Vehicle Mounted Satcom on the Move (SOTM) Communication Application

In this paper, a novel circularly polarized (CP) ridge-waveguide slotted antenna array is proposed for vehicle used Satcom on the Move (SOTM) applications. The antenna array is designed closely following the required factors for generating the circular polarization. The proposed antenna array is constructed on a symmetrical single-ridge slotted waveguide. Each antenna element consists of a pair of inclined slots opened on the narrow walls, and longitudinal slots opened on the bottom of the U-shaped wall of the waveguide. The inclined slots and the longitudinal slots are able to radiate orthogonal electric-fields independently with a phase-difference of 90°. After a vector superposition in the far-field by using this design, the circular polarization could be realized with extremely low axial ratio theoretically. Several essential parameters affecting the CP performance are also studied in this paper. To verify the feasibility of the proposed approach, a four-element CP antenna array is simulated, fabricated and measured. Results show that the obtained prototype achieves a measured impedance bandwidth of 14.74% from 9.24 GHz to 10.71 GHz with S11 <−10 dB, and a 3-dB axial ratio bandwidth of 19.1% from 9.0 GHz to 10.9 GHz.

Millimeter-Wave Endfire Wide-Angle Scanning Circularly Polarized Antenna Array

Because the width of antenna elements exceeds half of the air wavelength, resulting in too large element spacing, the scanning angle of traditional endfire circularly polarized (CP) antenna array is usually less than 60°. In order to solve the above problem, a CP quasi-Yagi antenna element is proposed in this letter, whose width is less than half of the air wavelength. Further, an 1 × 8 endfire CP antenna array is designed. Because the element spacing is about half a wavelength, the scanning angle of the proposed endfire CP antenna array can reach 60°. Moreover, the axial ratios of all beams are less than 3 dB in the scanning angle range of (0°, 60°). The final measured results are basically consistent with the simulated results

A low‐profile sequential‐phase fed circularly polarized array antenna with an irregular ground

Grooving or subtracting a projection of the antenna on the ground is one of the effective methods to both improve the axial-ratio (AR) bandwidth and impedance bandwidth of a circularly polarized (CP) antenna. A bidirectional radiation, meanwhile, can be produced. Unfortunately, these methods will result in a decrease in the gain of the antenna due to a reduction of its ground size. To solve this issue, a conductive plane or a cavity is usually introduced at the antenna's bottom, but it will lead to a high profile and destroy the bidirectional radiation of the design. In this article, a CP array antenna based on a sequential-phase (SP) feeding network is taken as an example. Only the projection of the feeding network is preserved, while other conductors on the ground are subtracted. The simulated peak gain of this design is only 5.04 dBic. In order to obtain an ultra-wideband, a wide AR bandwidth, a moderate gain and a low profile of the antenna, a method of etching a circle of ground around the edge of the substrate is presented to expand the ground into a large irregular area. The measured results show that the proposed design can exhibit a 90.9% 10-dB impedance bandwidth, a 42.4% (5.2–8 GHz) 3-dB AR bandwidth, a 7.17 dBic peak gain, and a very low profile of 0.006λL. This method is very simple to implement and does not need to modify the original antenna structure. It may be applied to conveniently improve the performance of the bidirectional radiation CP antenna.

A Novel Design of Flat-Top Beamforming Anti-Multipath Antenna

This article discusses a novel design method of wide-beam circular polarization array antenna for satellite navigation. For special applications such as satellite navigation guiding aircraft landing, high-performance ground reference station antennas are required. In the system of satellite navigation guiding aircraft landing, the antenna of satellite navigation receiver needs to have the following radiation characteristics: the shape of antenna pattern is close to an ideal hemisphere, the upper half of space has uniform right-hand circular polarization gain, and the beam has the characteristic of sharp cutoff below 5 degrees of elevation. Whether the GNSS reference station antenna can have a wider beam circular polarization characteristic to receive more navigation satellites signal; whether it can suppress the multipath effect to a greater extent to reduce the multipath error; and whether it can work in a wider frequency band, so that several major satellite navigation systems work together, the above factors directly affect the satellite navigation and positioning accuracy of the entire system. The beam of this antenna has the following feature: sharp cutoff near the horizon for multipath mitigation at low elevation angles. Comprehensive design thereby accelerates system design. It owns wide beam, good circular polarization characteristics, low elevation angle sharp cutoff, and ultralow sidelobe radiation characteristics that achieve the purpose of receiving satellite navigation signal and multipath. The low sidelobe characteristic of the antenna is beneficial to suppress multipath effect. According to the theoretical knowledge of the symmetrical dipole and the four-arm helical antenna, the simple structure of the symmetrical element is fully utilized, and the printed balun easily realizes the dual-frequency operation of the antenna. Combined with the wide-beam circular polarization characteristic of the four-arm helical antenna structure, the shaped beam array antenna is designed. The wide-beam circularly polarized antenna unit not only covers the frequency band of the satellite navigation system but also satisfies the system performance and key feature requirements of the array antenna for the unit; that is, it satisfies the wide-beam circular polarization characteristics of the upper half space. According to the linear array basic theory and array antenna synthesis theory, Woodward Lawson sampling synthesis algorithm is used to synthesize the array amplitude and phase weights corresponding to the specific antenna pattern required for the Ground-Based Augmentation System (GBAS) engineering. The shaped beam array antenna consists of 21 units, of which 11 antenna units are directly fed, and the feeding ports of the rest are dummy ports. It is an equally spaced array antenna. The spacing between antenna units is close to half wavelength. They are fed according to the value corresponding to the excitation function. The array antenna is simulated by HFSS (High-Frequency Structure Simulator). Compared with traditional satellite navigation antennas, the antenna in this paper has excellent front-to-rear ratio and flat-top beam pattern. The results show that the wide-beam circularly polarized array antenna meets the engineering requirements of GBAS applications and lays the solid foundation for GBAS engineering applications.

Wide Bandwidth Axial Ratio Circularly Polarized Array Antenna based on External Resonator

This study introduces a wide bandwidth and wide axial ratio (AR), circularly polarised (CP), patch array antenna. By combining dual layers of a polarizer with dual layers of linearly polarized microstrip patch antenna, a novel method is created for generating circular polarization waves with a wide frequency range. The dual-layer 2 × 2 and 2 × 8 microstrip patch array antenna is employed to achieve linearly polarized waves and the external polarizer consists of a 3 × 3 and 3 × 12 four-layer dual rings polarizer that transforms linearly polarized (LP) waves into CP waves. The |S11| −10 dB bandwidth of small and large-scale circular polarized array antennas is 20% and 27.06% at 5 GHz, respectively, Simulations and testing show that the 3-dB axial ratio bandwidth (ARBW) at 5 GHz is 17%. The suggested antenna has a lot of potential for satellite communication applications because of its easy structure, wide ARBW, and wide impedance bandwidth.