Circularly polarized transmit-array with sequentially rotated elements in Ka band

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.

Minimum audible angle (MAA) and minimum audible movement angle (MAMA) thresholds were measured for stimuli in horizontal, vertical, and diagonal (60 degrees) planes. A pseudovirtual technique was employed in which signals were recorded through KEMAR's ears and played back to subjects through insert earphones. Thresholds were obtained for wideband, high-pass, and low-pass noises. Only 6 of 20 subjects obtained wideband vertical-plane MAAs less than 10 degrees, and only these 6 subjects were retained for the complete study. For all three filter conditions thresholds were lowest in the horizontal plane, slightly (but significantly) higher in the diagonal plane, and highest for the vertical plane. These results were similar in magnitude and pattern to those reported by Perrott and Saberi [J. Acoust. Soc. Am. 87, 1728-1731 (1990)] and Saberi and Perrott [J. Acoust. Soc. Am. 88, 2639-2644 (1990)], except that these investigators generally found that thresholds for diagonal planes were as good as those for the horizontal plane. The present results are consistent with the hypothesis that diagonal-plane performance is based on independent contributions from a horizontal-plane system (sensitive to interaural differences) and a vertical-plane system (sensitive to pinna-based spectral changes). Measurements of the stimuli recorded through KEMAR indicated that sources presented from diagonal planes can produce larger interaural level differences (ILDs) in certain frequency regions than would be expected based on the horizontal projection of the trajectory. Such frequency-specific ILD cues may underlie the very good performance reported in previous studies for diagonal spatial resolution. Subjects in the present study could apparently not take advantage of these cues in the diagonal-plane condition, possibly because they did not externalize the images to their appropriate positions in space or possibly because of the absence of a patterned visual field.

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 new decoupling feeding network (DFN) is proposed for circularly polarized (CP) patch arrays with an arbitrary number of elements. Different from linearly polarized (LP) patch arrays, a dual-feed structure is adopted for each element to enhance the CP performance. The dual-feed structures should be integrated into the DFN, and hence the coupling paths become very complicated. An orthogonal mode decomposition (OMD) method is established to analyze the coupling mechanism between the CP patch elements. Based on the OMD, a network model of the mutual coupling between the CP patch elements is established, which can be used to assist design of the DFN. To verify the decoupling effect, a prototype of a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $ </tex-math></inline-formula> 2 CP patch array for a satellite navigation system is fabricated and measured. After applying the DFN, mutual coupling between all ports is reduced to below −33 dB at the center frequency of 1.26 GHz, and the decoupling effects reach 15–23 dB. The CP patch array maintains stable radiation patterns with a realized gain of ~9.4 dBi. The proposed OMD approach is applicable to other CP arrays with an arbitrary number of elements.

Array antennas offer a wide range of opportunities in the variation of their directivity patterns through amplitude and phase control. Peak sidelobe levels may be reduced via amplitude control or weighting across the array aperture. Several authors have made significant contributions in detailing processes for synthesizing these aperture amplitude distributions for the purpose of sidelobe level control. One of the basic trade-offs when implementing amplitude weighting functions is that a trade between low sidelobe levels and a loss in main beam directivity always results. Some of the commercially available pattern calculation programs that can implement sidelobe level control do not provide calculations of the aperture efficiencies given different amplitude weightings. Calculation of the aperture efficiency can be somewhat confusing, particularly with regards to the difference between tapering via attenuation versus redistribution. The purpose of this paper is to define these terms, to provide a review of the proper normalization technique that is important in obtaining accurate aperture efficiency estimation. Descriptions of the amplitude tapers and their utility will be presented. A design example will be presented which will compare theoretical efficiencies with those obtained via finite element method simulation.

A circular polarization (CP) patch antenna is proposed for the first time in this article. The proposed antenna is developed based on a patch antenna combined with one row of diagonal periodic metallic via holes. By optimizing the location of the periodic metallic via holes, two orthogonal waves with 90° phase difference are excited using single feed and a CP patch antenna is obtained. A CP antenna is designed based on the proposed structure and simulated by Ansoft HFSS. The designed CP antenna is fabricated and measured. The measured results present return loss |S11| > 10 dB from 10.4 to 11.6 GHz. The radiation pattern is also measured, and it exhibits good circular polarization property with 3-dB axial ratio (AR) of 1.2 dB and gain of 4.02 dBic. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett1100, 2013; 1097 this 1100 online at wileyonlinelibrary.com. DOI 10.1002/mop.27529

In this paper a novel circularly polarized (CP) leaky-wave antenna (LWA) based on the corrugated substrate integrated waveguide (CSIW) is proposed. It is composed of eight slot pair elements on top surface of the CSIW, and is designed to operate around 16.4GHz. The design approach is based on the analysis and optimization of the aperture fields of one radiation unit cell in order to produce good performance of circular polarization. The simulation results show that broadside radiation can be realized that is useful in practical application, and good axial ratio (AR) can be obtained in the main beam direction.

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 low profile and high gain circularly polarized (CP) antenna is investigated in this paper. The CP antenna consists of two orthogonal metallic strips and periodic shorting slices on their edges. The strips are fed with 90-degree phase difference at the corner by a single coaxial probe to realize circular polarization. Then four metallic strips are arrayed in sequential rotation and fed by a compact 3/4 ring. The simulated 10-dB impedance bandwidth and 3-dB axial ratio bandwidth are 30.9% (6.76–9.23 GHz) and 18.8% (6.75–8.15 GHz), respectively. The CP antenna with a low profile of $\sim 0.06 \lambda_{0}$ has a peak gain of 13.3dBi.

This paper presents the design and development of sequentially rotated broadband circularly polarized stacked patch array antenna for data & voice communication in MSS service. A Sequential rotation technique is used for improvement in axial ratio in 2 times 2 array environment. The driven element is Electromagnetically Coupled square patch with dual edges fed by T power divider. A parasitic patch is used for increasing the return loss bandwidth and improvement in gain. The lower patch should be over excited and the upper patch should be loosely coupled to achieve maximum possible bandwidth. Measured gain is more than 15.5 dB and axial ratio less than 1 dB over the MSS band. Measured bandwidth is 40% for 10 dB return loss.

A dual-band circularly polarized array antenna with high isolation is presented in this paper. It can receive left-handed circularly polarized (LHCP) wave in K band and radiate right-handed circularly polarized (RHCP) wave in Ka band. Using a stacked structure, it realizes a low axial ratio (AR) in both bands and a high isolation in Ka band. The full wave simulations of the element and an 8×8 array show good performance.

A high gain Double Negative (DNG) metamaterial superstrate based Circularly Polarized (CP) microstrip patch antenna for Ka band satellite communication is represented in this article. The rectangular patch antenna is developed with shorting pins along the two orthogonal diagonals. Pairs of shorted pins are placed to generate two different modes for obtaining CP. A simple coaxial probe-feeding is used to excite the patch antenna at Ka band. A 4x4 array of rectangular-shaped slotted ring patches which exhibits the characteristics of negative dielectric permittivity and permeability at Ka band has been used as superstrate. The implementation of this DNG metamaterial-based superstrate enhances the right hand CP gain from 10.2 dB to 12.2 dB, which makes the overall antenna height to be 0.58 times of the free space wavelength (λ0). The proposed design shows minimum axial ratio of 1.42 dB near the magnetic resonance of 28.5 GHz which makes the structure suitable for satellite applications.

This paper proposes the switched beam antenna array at the center frequency of 2.45GHz with a bandwidth of 187 MHz, from 2.32 GHz to 2.51 GHz. The phase shifter of antenna utilizes a 4×4 planar Butler matrix with phase differences between its outputs of ±135° and ±45° to obtain four the different main beam directions. The proposed design is fully described including the patch antenna element, the antenna array, the phase shifter that forms the completed antenna array. The antenna array achieves a gain max up to 7 dBi, and the angles of the main beam directions of -41°, -12°, +15°, +48° in a horizontal plane. The beamwidth of the four main beams is from 26° to 31.8° in E-plane and from 38.5° to 55.4° in H-plane. The advantage of the antenna is the planar structure and compact dimension of 200×230mm2. The proposed antenna is suitable for ISM band.

The use of bandwidth for mobile and cellular networks has been increasing at an unprecedented rate, with applications in emergent areas such as smart vehicles and civil infrastructure, telemedicine, and remote education. The predicted increase of mobile network utilisation requires a high data rate capacity to transfer information through the network. The current limited capacity of the fourth generation (4G) mobile network is not expected to satisfy the predicted high data demand by 2020. To meet this requirement, a new fifth generation (5G) mobile network has been proposed. In order to reach the high capacity demands, the 5G requires a wide frequency bandwidth, which is not available in the sub-3 GHz frequency spectrum. Therefore, many international organisations have assigned the millimetre-wave band (mm-Wave), which includes 24, 28, 37, 39, and 60 GHz, as a frequency band for 5G. Using mm-Wave raises many challenges such as an increase in the path loss, radiation field absorbed by the human body, signal polarisation misalignment, and MIMO antenna footprint inside the mobile handset. Therefore, designing beam-steering, reconfigurable circular polarization, and compact MIMO antenna systems for 5G applications is important to cope with these challenges. Although there are some antenna systems were reported recently for mm-Wave 5G, they had limited steering angles, one polarization types or bulky antenna size. This thesis aims to solve the current challenges mentioned above by developing mm-Wave 5G antenna systems and in doing so makes three main contributions to the field of mm-Wave 5G antenna systems.As the path loss and radiated fields absorbed by surface layers of the human body increase at mm-Wave, emphasis is given into the development of the beam-steering antenna system, which is the first contribution of this thesis. The beam-steering technique aims at reducing the effects of electromagnetic field exposure on the human head, as well as maintain a consistent connection between the handset and the base station. A novel compact three-dimensional (3-D) beam-steering system of mobile handsets at 28GHz is proposed. It consists of dipole antenna arrays, power dividers and digital phase shifters. Nevertheless, a novel technique of connecting p-i-n diodes to build a phase shifter is proposed for better performance. The proposed design has the ability to steer the beam in a wide angle in 3-D. it relies on using both sides of a printed circuit board for a two-dimensional antenna array. Moreover, to further improve the performance of the beam-steering system, a tunable power divider for mm-Wave 5G is presented. It is used to tune the feeding amplitude of the beam-steering antenna array, and thus reduces the side-lobe level (SLL) of the antenna radiation pattern.n nThe second contribution is the development of two reconfigurable circular polarisation (CP) structures for 5G applications at mm-Wave. CP is an effective technique to mitigate signal polarisation misalignment, phase deviation and multipath effect problems. Electrical reconfigurable methods are used to switch the CP type by using p-i-n diodes. Firstly, an open-ended stub concept with a simple feed circuit is used to build a novel reconfigurable CP patch antenna. Then the same concept is developed to build a reconfigurable CP antenna array system using branch-line couplers, power divider, and 4 p-i-n diodes. The open-ended stub concept is found to be efficient in both designs by reducing the complexity and the number of the p-i-n diode switches compared to the reported existing CP antenna systems in the literature.MIMO is a major technology of 4G mobile antenna system and also has disruptive potential for mm-Wave 5G. Therefore, the third contribution is the development of new design approaches to integrate the current 4G with futurist 5G MIMO antenna systems. Integrating these two technologies in one structure leads to a reduction of the total MIMO antenna footprint significantly within handsets, where the available space is limited. To that end, two novel 5G/4G MIMO antenna systems are built. First, 5G/4G MIMO antenna system is proposed by using one structure; and it covers multiband mm-Wave spectrums (28, 37 and 39) GHz for 5G as well as sub 3 GHz for 4G.n Moreover, to further improve the gain especially at mm-Wave band, an antenna array structure is deployed to build another 5G/4G MIMO antenna system. This design integrates 5G and 4G operations into a single structure; and covers a wideband 23-29 GHz for 5G and frequency-tuning 2.05-2.70 GHz for 4G.The developed antenna systems reported in this thesis positively contribute to the antenna design domain and are expected to encourage safety, compactness, reliability, and a multiband antenna system for the mm-Wave 5G industry in near future.n