Multibeam Antenna Array Research Articles

A Diversity Receiver-Based High-Gain Broad-Beam Reception Array Antenna

A novel reception antenna configuration is proposed for achieving high gain and broad beam coverage at the same time. This is accomplished by combining a multibeam array antenna with a diversity receiver. Signals from different beams are merged by diversity receiver in the baseband level using the maximal ratio combining scheme. The proposed approach is implemented by integrating a dual-channel digital TV receiver, a four-dipole array, and a 4 × 4 Butler matrix. Two outputs of the array, which have beam maxima pointing away from the boresight by ±14°, are connected to the two receiver inputs. Sensitivity measurements are conducted for different incident angles to find lowest transmitter power levels permissible for DTV signal demodulation. Measured results of a reference single-beam antenna validates that its angular sensitivity profile is proportional to the antenna gain pattern, and the ones of the diversity receiver-based array confirm that the proposed method can combine receptions of the two beams coherently. The effective 3 dB beamwidth of the implemented antenna is doubled, and the gain maximum is comparable with the single-beam array.

Синтез и исследование сверхширокополосной планарной трехзеркальной системы.

Cylindrical mirror and mirror - lens systems are used as radiating systems for multibeam antenna arrays. In this case, the planar waveguide, in which the feed element is located, makes a 180-degree turn and forms a two-layer structure, the second floor of which is occupied by an array. Such a design is more compact than a one-story one, in which the Rotman lens is usually used as a focusing element. A two-mirror aplanatic system allows reducing aberrations and expanding the scanning sector in comparison with a single-mirror one, however, for the arrangement of the grating above the planar waveguide, one more rotation of the planar waveguide is required, i.e. a transition to a three-mirror system is necessary. This construction is considered in this paper. It is shown that the third mirror allows reducing aberrations in comparison with the two-mirror system. The work consists of two parts. In the first part, problems of synthesis and minimization of aberrations of a cylindrical three-mirror aplanatic system are considered. As a result of optimization of the parameters, the angle of view of 100 degrees is realized. In the second part, the scanning properties of a four-layer antenna based on a synthesized three-mirror system were studied. The results of the experiment confirmed the size of the scanning sector and the broadband properties of the multi-beam antenna based on a synthesized three-mirror system.

A 5G MIMO Antenna for Broadcast and Traffic Communication Topologies Based on Pseudo Inverse Synthesis

This paper proposes a new design of a dual-polarized base station antenna for sub-6-GHz 5G communication covering the band from 3.3 to 3.8 GHz. The proposed antenna offers a good impedance matching across the desired frequency band with $\text {VSWR} \le 1.5$ , a stable radiation pattern with a half power beam width of 65° ± 5°, and a high isolation between the ports with a small size and a low profile. The antenna is converted to a planar MIMO antenna array with low envelop correlation coefficients between the array elements to perform in either a broadcast or traffic communication topology whenever required. In the broadcast communication topology, the proposed MIMO antenna array covers a sector of 65° in the horizontal plane with three different down-tilted beam directions at 0°, 10°, and 20° in the vertical plane as conventional base station antennas used for 2G, 3G, and 4G. In traffic topology, the proposed MIMO antenna array can direct multiple beams to concurrent multiple users in a point-to-multipoint communication based on a novel pseudoinverse synthesis (PIS). The novel PIS is proved to be better than the other approaches which use spatial or frequency diversity as it possesses the advantage of the spatial diversity (by using a single frequency for multi-user coverage) and the advantages of the frequency diversity (by offering good steering capability and high directivity for each user). It is capable of radiating dynamic multiple beams simultaneously with an excellent flexibility and steering capability in real-time processing and outperforming other multi-beam antenna array methods. Thus, this new design is an ideal candidate for the new 5G mobile base stations.

Millimeter-Wave MultiBeam Aperture-Coupled Magnetoelectric Dipole Array With Planar Substrate Integrated Beamforming Network for 5G Applications

A modified topology of the 2-D multibeam antenna array fed by a passive beamforming network (BFN) is proposed by introducing two sets of vertical interconnections into the conventional array configuration. Different from the traditional design, the new array structure can be integrated into multilayered planar substrates conveniently, which has advantages of low loss characteristics, ease of realization, and low fabrication cost for millimeter-wave (mmWave) applications. A $4\times4$ multibeam antenna array that can generate 16 beams is then designed, fabricated, and measured in order to demonstrate the correctness of the proposed topology. As the crucial components of the design, two kinds of aperture-coupled magnetoelectric dipole antenna elements with multilayered feed structures and three types of vertical interconnections consisting of the vertical substrate integrated waveguides are investigated, respectively. Wide bandwidth of 16.4%, stable radiation beams, and gain up to 14.7 dBi are achieved by the fabricated prototype. The proposed array configuration provides a new mean to implement the relatively large size 2-D multibeam antenna arrays with planar passive BFNs, which would be attractive for future mmWave wireless systems used for 5G communications and other applications.

Modeling of the zones of the Earth surface illuminated by the directional patterns of active multibeam antenna arrays

A kinematic model of the motion of a spacecraft (SC) constellation along circular orbits and an expression for calculation of the number of SCs required to completely illuminate the entire Earth surface with the visibility cones of the directional patterns (DPs) of onboard antennas are presented. A simplified procedure for construction of multiple footprints of partial DPs formed by multibeam phased-array antennas on the Earth surface has been developed. Expressions for calculation of the slant distance, the grazing angle, and zones of visibility of the Earth surface from the SCs at the normal and oblique incidence of the antenna beam have been obtained. Numerical examples and the respective graphic illustrations are given.

Broadband Multibeam Antenna Arrays Fed by Frequency-Dependent Butler Matrices

A novel concept of multibeam antenna arrays operating in an octave frequency band has been presented. To achieve multiple beams in such a wide bandwidth N-element antenna arrays are fed by frequency-dependent Butler matrices which smoothly change their properties across the bandwidth. The proposed Butler matrices are designed in such a way that for the selected inputs their amplitude and differential phase characteristics feature the ones obtained for $N \times N$ Butler matrices at $f_{0}$ , whereas at $2f_{0}$ they feature the properties of $N/2 \times N/2$ Butler matrices. The proposed concept has been verified by measurements of a multibeam antenna array operating in 1.75–3.5 GHz frequency range and extended showing the possibility of designing antenna arrays with higher number of beams.

BUTLER MATRIX IN MICROSTRIP-SLOT TECHNOLOGY

The design of a 4 x 4 Butler Matrix for use in a multi-beam antenna array operating over wide frequency band is presented. In order to achieve wideband characteristics, the matrix uses microstrip-slot technology that employs two microstrip dielectric layers with a common ground plane and a coupling slot. The designed Butler matrix is compact in size and does not use crossovers. Its prototype is manufactured. The performance of the designed device is assessed via full-wave electromagnetic simulations and measurements.

Application of the Power-Vector Method for Adaptive Signal Processing in Multibeam Antenna Arrays

We consider an adaptive antenna array, which forms a great number of beams for the parallel or successive observation of space and ensures the maximum ratio of the signal power to the mean noise power at the output. An algorithm for adaptive signal processing in the basis of the power vectors is proposed and the regularized estimates of the weight vectors are obtained using the limited number of the input-process samples, which can be both greater and smaller (the case of a short sample) than the number of the elements. The results of simulation of the adaptive signal processing are given, which show the high signal-processing efficiency in the adaptive antenna array.

Miniaturized SIW Multibeam Antenna Array Fed by Dual-Layer 8 × 8 Butler Matrix

This letter presents a multibeam antenna array fed by a substrate integrated waveguide 8 × 8 dual-layer Butler matrix within the band from 28 to 31 GHz. The dual-layer structure is adopted aiming to achieve miniature, so that the size of the structure is reduced by more than 50% compared with similar single-layer design. The utilization of dual-layer structure also decreases the complexity of the whole Butler matrix. A 2 × 8 slot antenna array is used as the radiating portion to obtain high gains and relatively low side lobe levels. The proposed multibeam antenna array is fabricated and tested to verify the performances.

A Compact 38 GHz Multibeam Antenna Array With Multifolded Butler Matrix for 5G Applications

A compact 38 GHz multibeam antenna array is presented for fifth-generation applications. A beamforming network featuring a substrate integrated waveguide (SIW) multifolded 4 × 8 Butler matrix is constructed. Benefiting from multilayer structure, the Butler matrix is highly integrated and assembled underneath the radiators to achieve compactness. The Butler matrix is, then, combined with an 8 × 10 SIW slot-coupled patch array to establish four steering beams along the H-plane and to accomplish size reduction of 53.5% in its longitudinal direction. For demonstration, one prototype of the proposed antenna array was fabricated. The measured four beams point toward ±36° and ±12° with gains equal to 19.8 and 21 dBi, respectively.

Метод поиска сигналов радиоэлектронных средств в условиях сложной сигнально-помеховой обстановки с использованием многолучевых самофокусирующихся адаптивных антенных решеток

Метод поиска сигналов радиоэлектронных средств в условиях сложной сигнально-помеховой обстановки с использованием многолучевых самофокусирующихся адаптивных антенных решеток

Broadband Integrated <inline-formula> <tex-math notation="LaTeX">$8 \times 8$ </tex-math> </inline-formula> Butler Matrix Utilizing Quadrature Couplers and Schiffman Phase Shifters for Multibeam Antennas With Broadside Beam

A novel realization of a broadband $8 \times 8$ Butler matrix having phase progressions 0°, ±45°, ±90°, ±135°, and 180° has been proposed. The presented network is composed of coupled-line 3-dB/90° directional couplers and Schiffman phase shifters that ensure its broadband amplitude and phase characteristics. The proposed solution allows for a fully planar realization without any interlayer connections, which has been achieved by both rearrangement of the matrix layout and realization of the selected crossovers as tandem connections of quadrature directional couplers. The proposed concept has been verified experimentally by the design of a Butler matrix operating within 2.5–3.5 GHz and applied in a multibeam antenna array with broadside beam.

A Multibeam End-Fire Magnetoelectric Dipole Antenna Array for Millimeter-Wave Applications

A novel substrate integrated waveguide (SIW)-fed end-fire magnetoelectric (ME) dipole antenna is proposed. The antenna consisting of an open-ended SIW and a pair of electric dipoles has a simple structure that can be integrated into substrates conveniently. Both the open-ended SIW and the electric dipoles are effectively radiated together. Excellent performance, including a bandwidth of 44%, symmetrical radiation patterns that are almost identical in two orthogonal planes, low backward radiation, low cross polarizations, stable gain of around 5 dBi, and wide beamwidth of around 110°, are also obtained. An $8 \times 8$ SIW Butler matrix is then designed. Modifications to the geometry of the matrix provide more spacing to locate SIW phase shifters and phase compensation structures with wide bandwidth. By employing the proposed end-fire ME-dipole antenna array and the $8 \times 8$ Butler matrix, an eight-beam antenna array is realized. The fabricated prototype demonstrates that wide bandwidth, stable radiation patterns with cross polarizations of less than −28 dB and gain varying from 9 to 12 dBi can be obtained. The proposed multibeam end-fire ME-dipole antenna array would be an attractive candidate for millimeter-wave wireless applications due to its good performance, ease of integration, and low fabrication cost.

A Novel 2-D Multibeam Antenna Without Beamforming Network

A novel design of multibeam array antenna without feeding network is presented in this communication. This array antenna consists of $3\times 3$ microstrip patches as radiators. In this design, a feeding network is avoided where each patch is fed by a probe. Furthermore, whatever patch is excited, the input power can be coupled to all patches through four microstrip lines located between the radiating elements. In addition, nine radiation beams can be implemented depending on different field distributions that are generated by exciting each patch individually. The proposed antenna has a simple single-layered structure and does not suffer from a complex feeding network compared with traditional multibeam antennas. The experimental results demonstrate that the scanning ranges of the nine beams are ±24° and ±45° in the vertical and horizontal directions, respectively. Moreover, measured gain for the nine beams of the implemented antenna varies from 9.06 to 10.45 dBi.

Scalable Multibeam Antenna Arrays Fed by Dual-Band Modified Butler Matrices

A concept of dual-band multibeam antenna arrays that allows for efficient utilization of a common aperture has been proposed. The presented antenna arrays allow for achieving $N$ -independent beams pointing at $N$ different directions at higher frequency and $N$ -independent beams at lower frequency pointing at $N/2$ different directions and having two orthogonal polarizations. As feeding networks, novel modified Butler matrices (BMs) have been proposed in which directional couplers having different properties in two frequency ranges have been for the first time utilized. To confirm the theoretical analysis, a dual-band multibeam antenna array fed by a modified $4\times4$ BM has been developed operating in 2.4 and 5.2 GHz frequency ranges.

60-GHz LTCC Miniaturized Substrate Integrated Multibeam Array Antenna With Multiple Polarizations

In this paper, miniaturized substrate integrated multibeam array antennas are proposed and designed at 60 GHz. Owing to the design flexibility of the low temperature cofired ceramic (LTCC) technology, the entire multibeam antenna size is only equal to the size of radiating aperture by carefully embedding the complicated substrate integrated waveguide (SIW) feeding network underneath the radiating array. After introducing design procedures for the folded Butler matrix and the corresponding radiating array, a ± 45° dual linear-polarization (LP) and a dual circular-polarization (CP) substrate integrated multibeam array antennas are designed and fabricated, respectively. Here, each multibeam antenna has four switchable beams with different pointing directions. Each beam direction has two orthogonal LP or CP modes, therefore allowing the polarization diversity. Measured results validate our design and demonstrate good performances of our proposed structures.

A Multibeam Antenna Array Based on Printed Rotman Lens

A compact printable multibeam antenna array is studied in this paper. The antenna system is composed of a printed Rotman lens and an antipodal dual elliptically tapered slot antenna array; both of the two components are studied, respectively, at first, and then integrated on a single printed circuit board to make up the integrated unit of the multibeam antenna array. Measured results of all components are presented.

Design of Beam-Forming Networks for Multibeam Antenna Arrays Using Coherently Radiating Periodic Structures

The design of a beam-forming network (BFN) for a multibeam-steerable antenna array using Coherently RadiatingPeriodic Structures (CORPS) is presented. In this design, the input ports of the feeding network are optimized usingthe particle swarm optimization (PSO) algorithm. A two-beam design configuration of CORPS-BFN for a multibeamsteerablelinear array is proposed and analyzed. The results shown in this paper present certain interestingcharacteristics in the array factor response, in terms of sidelobe level (SLL) and directivity (D), for the scannablemultibeam linear array and the feeding network simplification for the design of BFN based on CORPS.

IMPROVED ARTIFICIAL BEE COLONY FOR DESIGN OF A RECONFIGURABLE ANTENNA ARRAY WITH DISCRETE PHASE SHIFTERS

Multi-beam antenna arrays have important applications in the fleld of communications and radar. The reconflgurable design problem is to flnd the element in a sector pattern main beam with side lobes. The same excitation amplitudes applied to the array with zero-phase should be in a high directivity, low side lobe pencil shaped main beam. This paper presents a new method of designing a reconflgurable antenna with quantized phase excitations using an improved artiflcial bee colony, called IABC. Compared with subsequent quantization, experimental results indicate that the performance of the discrete realization of the phase-excitation value can be improved.

A New Approach in the Simplification of a Multiple-Beam Forming Network Based on CORPS Using Compressive Arrays

This research paper deals with a innovative way to simplify the design of beam-forming networks (BFNs) for multibeam steerable antenna arrays based on coherently radiating periodic structures (CORPS) technology using the noniterative matrix pencil method (MPM). This design approach is based on the application of the MPM to linear arrays fed by CORPS-BFN configurations to further reduce the complexity of the beam-forming network. Two 2-beam design configurations of CORPS-BFN for a steerable linear array are analyzed and compared using this compressive method. Simulation results show the effectiveness and advantages of applying the MPM on BFNs based on CORPS exploiting the nonuniformity of the antenna elements. Furthermore, final results show that the integration of CORPS-BFN and MPM reduces the entire antenna system including the antenna array and the beam-forming network subsystem resulting in a substantial simplification in such systems.