Sequentially rotated broadband circularly polarized stacked Patch array antenna

Solar panel integrated compact magneto-dielectric loaded sequentially rotated navigation antenna

Two sequentially rotated, four stage, wideband circularly polarized high gain microstrip patch array antennas at Ku-band are investigated and compared by incorporating both unequal and equal power division based feeding networks. Four stages of sequential rotation is used to create 16×16 patch array which provides wider common bandwidth between the impedance matching (S 11 < −10dB), 3dB axial ratio and 3dB gain of 12.3% for the equal power divider based feed array and 13.2% for the unequal power divider based feed array in addition to high polarization purity. The high peak gain of 28.5dBic is obtained for the unequal power division feed based array antennas compared to 26.8dBic peak gain in the case of the equal power division based feed array antennas. The additional comparison between two feed networks based arrays reveals that the unequal power divider based array antennas provide better array characteristics than the equal power divider based feed array antennas.

A wideband 2 &#x00D7; 2 sequential-phase fed circularly polarized (CP) microstrip antenna array (MAA) with sequentially rotated elements is proposed. Firstly, the antenna element loaded with shorting pins is studied as compared to the traditional counterpart. Then, a feeding network is designed to be connected together in a sequential rotation manner, resulting in forming a four-port network to allow symmetrical positioning of CP microstrip patch elements. After that, straight strips are added to the feeding network in order to increase the distance and reduce coupling between array elements. They also play a role in improving the impedance matching of the array. Finally, the proposed antenna array is designed and simulated. The results are presented that its impedance bandwidth is about 36.3% at 24.1&#x007E;34.8 GHz for &#x007C;S<inf>11</inf>&#x007C; &#x003C; &#x2212;10 dB and axial-ratio (AR) bandwidth is about 20.4% at 24.2&#x007E;29.7 GHz for AR &#x003C; 3 dB. Besides, a peak gain of 11.1 dBic is simulated over the operating frequency range, which is significantly improved compared to the classic and existing works.

Circular polarization is indispensable for robust wireless communication between mobile devices that operate at mm-wave frequencies. Additionally, phased-array solutions are required to cope with the associated free space path loss. In view of the size constraints for antennas integrated on (Bi)CMOS chips, an array of linearly polarized dipoles using a sequential rotation scheme is an attractive approach to comply with all mentioned requirements. When steering such an array off broadside, however, the axial ratio will severely degrade. It is the purpose of this communication to demonstrate how the axial ratio can be retained by compensating the amplitudes and phases of the individual antenna elements. Measured results on a 6 GHz test-bed show that the axial ratio with the proposed calibration scheme remains below 3 dB within the 3 dB beamwidth of the scanned beam. Results from a 60 GHz test-bed confirm the effectiveness of the method.

This paper presents a novel random sequential rotation (RSR) technique for good side lobe suppression and axial ratio control of the phased array, based on characteristic mode analysis (CMA). The principle of good side lobe and axial ratio (AR) are analyzed through one 16-element single-chamfered circularly polarized array, utilizing regular, sequential rotation (SR) and RSR arrangements for comparison. The simulation results show that the proposed RSR array can effectively improve the side lobe and axial ratio properties especially in its diagonal plane.

A wideband strip-helical antenna with a parasitic circular patch for circular polarization is designed in this paper. A strip-helix with 2.5 turns and a pitch angle of 5° is placed over a ground plane and coaxial probe-fed by a 50- $\Omega $ SMA connector. A parasitic patch is electromagnetic-coupled to the open end of the strip-helix with an extremely small distance. By combining the strip-helix with the parasitic patch, two nearby circularly polarized (CP) resonances are produced and a wide axial ratio (AR) bandwidth is obtained. The strip-helix can excite a CP resonance in axial mode, while the parasitic patch can generate another nearby one in fundamental mode. Radiation characteristics of the proposed design, including current distributions, reflection coefficient (S11), AR, and radiation patterns, are studied. Measured results shows that the proposed antenna has an impedance bandwidth (S11 ≤ − 10 dB) of 53%, an AR bandwidth (AR ≤ 3 dB) of 44%, and a peak gain of 9.4 dBi in its volume of $0.43\lambda _{0} \times 0.43\lambda _{0} \times 0.25\lambda _{0}$ , where $\lambda _{0}$ is the wavelength in free space at the center operation frequency.

This paper presents the design of dual circularly polarized (CP) series-fed arrays based on the sequential rotation (SR) technique with uniform radiation elements. The radiation elements and feeding network used in the array are uniform, which leads to the possibility of dual-CP radiation by series-fed SR arrays. Meanwhile, the elements radiate unequal powers due to this arrangement. The relationship between the axial ratio and four key parameters of the array is derived and thoroughly discussed. Good polarization purity and port isolation can be realized by optimizing these parameters. A dual-CP array working at 10 GHz is designed with the help of the analysis. The experimental results show that the proposed antenna has good properties.

In this paper, a wide-angle beam scanning circularly polarized (CP) phased array element, which consists of a concentric tightly coupled dipole array (TCDA) element with a two-layer parasitic ring structure and a wideband 90° phase shifter, is proposed. To solve the problem of the scanning blindness zone caused by a concentric layout, the grounded coupling patch for the traditional TCDA element is ‘split’ into a combination of a grounded parasitic ring and coupling patch. This combination structure can not only suppress the in-band common-mode resonance but also destroy the scanning blind zone mode formed by the dipole and grounded coupling patch. In addition, a two-layer parasitic ring structure is introduced to obtain a wider axial ratio (AR) beamwidth relative to a single-layer structure, so a wide-angle beam scanning AR is realized. An 8 × 8 left-handed CP planar array based on the proposed wide-angle beam scanning CP elements is designed and prototyped. Results show that the array can operate over a 3.2:1 (3.75–12.0 GHz) overlapping bandwidth, meeting an AR < 3 dB in the main beam and an active voltage standing wave ratio <2.8 within a ±60° angle scanning range.

Circularly polarized radiation is frequently used in satellite communication. This paper discusses how circular polarization can be generated by means of an array of linearly-polarized antenna elements by applying the sequential rotation technique. A calibration method is used to improve the axial ratio from ±30° to ±60° off bore sight by using a 4-bit accuracy for the active components. A measurement campaign was organized based on a demonstrator developed at ASTRON. The calibration of the axial ratio is applied to the measured element patterns of the ASTRON egg-crate structure antenna array operating at 7.14 GHz. The results prove that the axial ratio can be improved significantly. Finally the same technique will be applied to a linear array operating at 20 GHz with sequential rotation configuration in front of the reflector to improve the axial ratio in the boresight direction.

A single-feed excitation mechanism for a circularly polarized (CP) two-layer printed circuit board (PCB) antenna based on sequential rotation (SR) is introduced. A coaxial connector drives two microstrip lines with opposite phase, which in turn couple to slotlines in the ground plane through a symmetric two-arm structure terminated in via holes. The slotlines feed four SR dipoles working at around 2.45 GHz, with a reflector added below at a distance of λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf>/4 to improve broadside radiation. The fabricated prototype is measured in the anechoic chamber, yielding an impedance bandwidth (BW) (|S<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf>| < −10 dB) of 29.2% and an axial ratio (AR) BW (|AR| < 3 dB) of 4.3%.

In this article, a wideband (22–28 GHz), polarization reconfigurable, flat panel, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 transmit (Tx)/receive (Rx) phased array antenna (PAA) is proposed. The array offers a realized gain of 22–23 dBi/dBic in the broadside direction and scans to approximately ±50° while maintaining 3-dB gain drop/scan loss, low cross-polarized fields, and axial ratio (AR) below 3 dB [in the case of circular polarization (CP)] over the entire bandwidth within the given scan range. By utilizing the amplitude and phase control mechanism of the radio frequency integrated circuits (RFICs) employed for the beamforming network (BFN), every single radiating element of the array can work in four polarization cases, such as horizontal ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula> -), vertical ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Y$ </tex-math></inline-formula> -), left-hand circular and right-hand circular polarizations (CPs). The single element is a novel stacked patch configuration with text L-shaped stubs at the two opposite corners of the driven patch and stubs on radiating edges of both the driven and parasitic patches. The radiator offers a wideband performance in addition to resolving the poor isolation between the two ports, thereby improving the text cross-polarized fields and AR over the entire bandwidth. The radiating elements are arranged in a unique way in the array such that the benefit of element mirroring is achieved during the dual linear cases, whereas the benefit of sequential rotation of elements is achieved in dual CP cases, which further improves cross-polarized fields and AR. The simulated results are validated through the measurement results for a fabricated PAA prototype for the scanned radiation patterns for all four polarizations in the Rx mode, the antenna gain-to-noise temperature (G/T) in the Rx mode, and effective isotropic radiated power (EIRP) in the Tx mode.

A new design of circularly-polarized (CP) transmit-array is proposed for SATCOM applications with reduced axial ratio in the main beam direction. The unit-cell is formed by a linearly-polarized rectangular patch (receiving layer) connected to a CP patch (transmitting layer). The full-wave simulations show an insertion loss level (IL) of 0.2 dB at 30 GHz with a 1-dB bandwidth of about 9.4%. The sequential rotation of the CP patches has been implemented in order to further improve the polarization purity. The different distributions considered lead to a significant improvement of the cross polarization discrimination (XPD) with gain, side-lobe level and efficiency close to the configuration without rotations. Tilted-beam radiation patterns in the horizontal and diagonal planes will be also presented.

A novel patch phased array antenna with improved scanning performance is presented in this paper. The active element pattern is changed as desired through a modified SIW cavity, resulting in an extension of the phased array’s 3 dB scanning range. Furthermore, sequential rotation is used to reduce the cross-polarization level of the array, which also improves the scanning gain at ±45°. Without altering the element size or profile, the array has the merits of low cost, low complexity, and a simple feed structure. The presented phased array antenna (PAA) exhibits a gain fluctuation of less than 2.2 dB when steering to 45°. Furthermore, the cross-polarization levels are below −68.1 dB when scanning to 45° in a E-/H-plane over the whole working band. To validate the proposed design, a prototype of a 24 × 16 active PAA is designed, fabricated, and measured. A good agreement between the simulated and measured results is achieved, Thus, this paper offers a viable solution to enhance the scanning performance of a PAA with fixed interelement spacing.

An unconventional, yet quasi‐modular base station phased array architecture synthesis technique is proposed for multiuser fifth‐generation applications. By keeping uniform amplitudes and linearly progressing phases at the elements of an optimal irregular array, power‐efficient side lobe suppression is achieved for effective inter‐user interference mitigation. The layout irregularity is achieved within a slice of an array, which is repeated rotationally. The sequential rotation technique is applied to obtain modularity and improve the circular polarization characteristics. A modified k‐means clustering algorithm is used to form the optimal subarrays. The simulation results indicate that the proposed quasi‐modular topologies provide a good compromise between the side lobe performance and integrated array design complexity.

A low loss dielectric rod waveguide design is proposed for use at Ku band. Measured waveguide performance from 10 to 18 GHz is presented and validated using full wave numerical simulations. The proposed design uses a low permittivity cladding to improve performance at the low end of the operating frequency band. Moreover, an improvement of the waveguide isolation due to the cladding is analyzed as well. The proposed ABS cladding is also implemented on a dielectric end-fire antenna obtaining an improvement in return loss, gain and half power beamwidth at the low end of the Ku band; the measured peak gain at 12.2 GHz is 14.6 dBi and 9.8 dBi with and without the cladding, respectively, and the 3 dB beamwidth changes from 22 to 61 degrees.