Compact Antenna Array Research Articles

Experimental Study of Electrically Compact Retrodirective Monopole Antenna Arrays

Auto-pointing and angular super-resolution properties of the radiation patterns generated by an electrically compact retrodirective monopole antenna array are demonstrated experimentally for the first time. The operation of electrically compact (element spacings less than one-fifth of the radiation wavelength) retrodirective antenna arrays that were theoretically considered in our previous work is confirmed by measurement. Particularly, it is shown that the direction-of-arrival information carried by an incident electromagnetic wave can be encoded into the evanescent near field of an electrically small resonant antenna array with a spatial rate higher than the spatial oscillation rate of the incident field in free space. This observation is supported by the near-field measurements, demonstrating that the magnitude of the scattered (evanescent) field in the array environment can exceed the magnitude of the incident field in free space by at least 6 dB. Retrodirective array antenna matching and the feasibility of a frequency-division full-duplex communication link based on the proposed antenna arrays are also discussed.

Compact log‐periodic dipole array antenna with bandwidth‐enhancement techniques for the low frequency band

A compact planar log-periodic dipole array (LPDA) antenna operating from 0.55 to 9GHz with high measured gain is proposed to be implemented in a reverberation chamber as a source antenna. To minimise the total size of the LPDA antenna, variants of top-loading techniques are utilised, and a much smaller spacing factor is opted to specify the spacing between the elements. However, miniaturisation of the LPDA antenna limits the antenna's wideband characteristics over the desired range of frequencies. Hence, a feedline meander and a trapezoidal stub are incorporated into the design as impedance matching techniques to effectively enhance the bandwidth performance especially for the lower band of the antenna's operating frequency range. The LPDA antenna exhibits radiation patterns with and without a radome having the measured gain ranging from 2.48 to 7.89 dBi and from −1.20 to 7.94 dBi, respectively.

Design of Compact Reconfigurable Miniaturized Triple-band filtenna for IoT Applications

The Microstrip Patch technology offers a compact Triple-band Antenna for IOT Application achieves reduced filter size and desired output. Novel Compact Microstrip Patch Antenna and 2x2 Antenna Array with Band Pass Filter for IoT Application in WSNs/WLAN/LTE bands is proposed. The Compact rectangular antenna is designed with inverted C Shape for the dual band resonance at 3.5/5.8 GHz and the 2x2 antenna array is designed for the triple band resonances at 2.4/3.5/5.8 GHz fed with 50Ω microstrip feed line to support WSNs/WLAN/LTE bands for IoT Applications. The parameters such as Return Loss, Gain, Directivity, Radiation Pattern of the single antenna and antenna array are obtained with high performance. The single antenna shows directional radiation pattern with the gain value of 4dBi and 6.5dBi and resonates at 3.5/5.8 GHz. The antenna array shows directional radiation pattern with the gain value of 5/7/9 dBi and resonates at 2.4/3.5/5.8 GHz respectively. Finally the LPF and HPF are cascaded to develop a Band pass filter (BPF), for passing frequencies 2.4/3.5/5.8 GHz and analyzed. From the comparision of Single antenna and Antenna array, 2x2 Antenna array achieves highest performance with triple band resonance. The proposed antenna parameters are fabricated and analysed using Vector Network Analyser.

Performance Analysis of Compact FD-MIMO Antenna Arrays in a Correlated Environment

Full dimension multiple-input-multiple-output (FD-MIMO) is one of the key technologies proposed in the third Generation Partnership Project (3GPP) for the fifth generation communication systems. The reason can be attributed to its ability to yield significant performance gains through the deployment of active antenna elements at the base station in the vertical as well as the conventional horizontal directions, enabling several elevation beamforming strategies. The resulting improvement in spectral efficiency largely depends on the orthogonality of the sub-channels constituting the FD-MIMO system. Accommodating a large number of antenna elements with sufficient spacing poses several constraints for practical implementation, making it imperative to consider compact antenna arrangements that minimize the overall channel correlation. Two such configurations considered in this paper are the uniform linear array (ULA) and the uniform circular array (UCA) of antenna ports, where each port is mapped to a group of physical antenna elements arranged in the vertical direction. The generalized analytical expression for the spatial correlation function (SCF) for the UCA is derived, exploiting results on spherical harmonics and Legendre polynomials. The mutual coupling between antenna dipoles is accounted for and the resulting SCF is also presented. The second part of this paper compares the spatial correlation and mutual information (MI) performance of the ULA and UCA configurations in the 3GPP 3-D urban-macro and urban-micro cell scenarios, utilizing results from random matrix theory on the deterministic equivalent of the MI for the Kronecker channel model. Simulation results study the performance patterns of the two arrays as a function of several channel and array parameters and identify applications and environments suitable for the deployment of each array.

A New Compact and High Gain Circularly-Polarized Slot Antenna Array for Ku-Band Mobile Satellite TV Reception

A compact and high-gain SIW-fed circularly polarized (CP) slot-antenna array with a stacked feed structure is presented for the application of Ku-band high-data-rate satellite communications. First, a novel probe-fed SIW cavity with four slots etched on the top surface is proposed as a high-gain radiating element for the array. The four slots in the cavity act as a $2\times2$ array, and its directivity is 2.15 and 1.43 dB greater than that of the cavity-backed antenna of the same size using ring slot and split ring slot, respectively. Second, a compact 1–4 SIW power divider is designed for exciting a subarray. Third, the $2\times2$ subarray is further expanded to an $8\times16$ array by adopting an additional layer of 1–32 SIW feeding network to meet the gain requirement of the Ku-band mobile satellite TV reception. Finally, experiments are carried out to verify the designed prototypes. Measured results show that proposed 128-element array has a relative impedance bandwidth of 4.8% (11.84 to 12.42 GHz), AR bandwidth of 130 MHz (12.01 to 12.14 GHz), and a peak gain of 26.8 dBic at 12.06 GHz. Owing to the simple feeding networks and the compact radiating element, the antenna has a compact size of $6.04\lambda _{ {0}} \times 11.96\lambda _{ {0}} \times 0.1\lambda _{ {0}}$ . Experimental results show that the proposed CP antenna array is suitable for applications of Ku-band mobile satellite TV reception.

Isolation Enhancement in Patch Antenna Array With Fractal UC-EBG Structure and Cross Slot

A compact patch antenna array with high isolation by using two decoupling structures including a row of fractal uniplanar compact electromagnetic bandgap (UC-EBG) structure and three cross slots is proposed. Simulated results show that significant improvement in interelement isolation of 13 dB is obtained by placing the proposed fractal UC-EBG structure between the two radiating patches. Moreover, three cross slots etched on the ground plane are introduced to further suppress the mutual coupling. The design is easy to be manufactured without the implementation of metal vias, and a more compact array with the edge-to-edge distance of 0.22 λ0 can be facilitated by a row of fractal UC-EBG, which can be well applied in the patch antenna array.

A Multiband Millimeter-Wave 2-D Array Based on Enhanced Franklin Antenna for 5G Wireless Systems

This letter presents a novel and compact antenna array suggesting geometrical modifications in the concept of collinear arrays at millimeter-wave (MMW) spectrum. The extension of the standard narrowband Franklin linear antenna array in a compact 2-D assembly is proposed and multiband response is accomplished in this work, which fulfills demands of future fifth-generation (5G) systems. The proposed 2-D antenna array is designed to operate at licensed frequency bands of 28 and 37–39 GHz recommended by the U.S. Federal Communications Commission for 5G wireless networks, as well as at 33 GHz for satellite communication and navigation applications. Measurements validate the triple-band response at the desired frequencies of operation. The proposed antenna array also offers distinguishing performance in terms of high gain and significant efficiency above 70% in all the MMW operating bands.

A Novel Time-Based Beamforming Strategy for Enhanced Localization Capability

The letter describes an original time-based driving strategy of a compact antenna array suitable for future 5G Internet of Things (IoT) applications. Subsets of array elements are selectively activated in real-time for agile and precise localization of tagged objects, randomly distributed in harsh electromagnetic environments. A new layout, starting from a standard time-modulated array (TMA) solution, is implemented, which allows us to fruitfully exploit the sideband radiation capability, typical of this array family. One radiating element of the array is replaced by a multiantenna architecture, thus enabling the designer to have a total control of the maximum radiation direction of the array not only at the sideband harmonics, as for standard TMAs, but also at the fundamental. In this way, an extremely accurate localization capability is obtained by properly driving the nonlinear switches at each antenna port, without resorting to complex feeding networks or phase shifters. The antenna system design must be carried out through an accurate circuit/electromagnetic cosimulation approach, thus accounting for the electromagnetic couplings among the radiating elements and the nonlinear behavior of the switches. This is demonstrated with a compact-size planar patch array operating at 5.8 GHz compatible with portable device equipment for concurrent future wireless operations.

Left-handed compact MIMO antenna array based on wire spiral resonator for 5-GHz wireless applications

A compact coplanar waveguide-fed multiple-input multiple-output antenna array based on the left-handed wire loaded spiral resonators (SR) is presented. The proposed antenna consists of a 2 × 2 wire SR with two symmetrical microstrip feed lines, each line exciting a 1 × 2 wire SR. Left-handed metamaterial unit cells are placed on its reverse side and arranged in a 2 × 3 array. A reflection coefficient of less than −16 dB and mutual coupling of less than −28 dB are achieved at 5.15 GHz WLAN band.

Experimental investigation on the effect of user's hand proximity on a compact ultrawideband MIMO antenna array

An experimental study of the interaction between user's hand and an ultrawideband multiple-input multiple-output (MIMO) antenna array is presented for mobile terminals. The dual-element array covers the frequency ranges 698–990 MHz and 1710–5530 MHz with a good efficiency in free space. Depending on the standard, it can be used for channel sensing in cognitive radio networks or for communications in cellular networks. Hand phantoms for three usage scenarios are used for the investigation, namely, personal digital assistant (PDA) right hand, PDA left hand, and two hands. The absorption in the immediate located hand is the main factor causing degradation of the total efficiency (slightly affected by the hand induced changes in the S-parameters), reduction and imbalance in the antennas mean effective gain contributing to a deteriorated diversity gain (DG). The user caused changes in the antennas radiation patterns reduce the correlation in the lower band which enhance the DG and multiplexing efficiency. The exposure of the hand in each scenario is studied by the specific absorption ratio.

15 GHz grid array antenna for 5G mobile communications system

ABSTRACTA compact grid array antenna implemented using FR4 substrate for 5G Mobile Communications at 15 GHz is presented. The antenna with dimensions of 49 mm × 58 mm × 1.6 mm has 23 radiating elements to provide high gain. It is excited using coaxial feeding technique. Measurement of the fabricated prototype for the simulated antenna was carried out. Both measured and simulated results agree with each other. The measured result shows that the antenna has achieved an impedance bandwidth of 14% from 13.8 GHz to 15.9 GHz with a gain of 14.4 dBi at 15.9 GHz. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2977–2980, 2016

Compact Patch Antenna Array using Defective Ground Structure on Feedline

The paper presented here is dealing with the design of compact patch antenna array using defective ground structure (DGS) on feed line. The array of 1:2 patch antenna with microstrip line feeding technique is proposed. A systematic approach has been taken to design the antenna array using defective ground structure on the feed line to achieve the return loss up to -56dB. The designed antenna is suitable for WIMAX application.

Contribution of LPP/ERM-KMS to the modern developments of ICRH antenna systems

The paper gives an overview of the coupling physics of an ICRF antenna array to the plasma and of the original conceptual solutions proposed by the LPP/ERM-KMS group for the compact ITER antenna array and its matching to the RF power sources. The main contributions are (i) the use of an array of short straps grouped in triplets, (ii) the triplet feed by a four port junction and the use of a service stub to enlarge its frequency response, (iii) the multistep prematching to decrease the VSWR and minimise the voltage in the feeding transmission lines, (iv) the use of a decoupler network to neutralize the mutual coupling effects between different RF power sources and to simultaneously control the current distribution of the antenna array, (v) the various options to connect the decouplers and 3dB hybrids for different array phasing cases in order to maintain the correct functioning of the decouplers together with load resiliency to fast variations of the plasma density in the edge (caused by e.g. pellet injection or Edge Localized Modes), (vi) the solution of the grounding problem of the ITER antenna plug-in, (vii) the test on mock-ups in front of a dielectric dummy load of the performance of the different solutions and particularly of the automatic matching and decoupling control of the complete ITER antenna array.

Super-resolution characteristics based on time-reversed single-frequency electromagnetic wave

ABSTRACTA sub-wavelength three-antenna array that is able to perform super-resolution focusing with single-frequency signal excitations is investigated using time-reversal. The antenna array is loaded with a set of uniformly distributed thin metal wires, which when combined with single-frequency electromagnetic waves from a time-reversal mirror yields a 1/35 wavelength super-resolution focusing at the targeted antenna. The length of the metal wires in particular determines the frequency band enabling super-resolution performance. The results have significance for the super-resolution investigation of multi-band compact antenna arrays involving micro-structures, with potential linkage with recent studies on super-resolution mechanisms in deterministic complex media.

Ku-band dielectric resonator antenna array for microwave imaging

In this article, a compact dielectric resonator antenna array was proposed for microwave imaging systems. Four resonator elements of Roger RT/Duroid 6010 were used over the FR4 substrate for an array configuration with a total size of 35 × 50 × 7 mm. The proposed antenna array attained wide operational bandwidth of 6 GHz ranging from 12 to 18 GHz making antenna effectively operational for whole Ku-band. The demonstrated antenna along with being wide-band and small size, possessed essential performance characteristics like appropriate gain, stable radiation patterns, and high radiation efficiency over the entire band, therefore, making proposed antenna a prospective candidate for microwave imaging. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1651–1655, 2016

격리도 향상을 통한 배열안테나의 성능개선 연구

Abstract In this paper, we have studied isolation enhancement using a suppression of surface wave to improve performance of array antenna. To reduce isolation between elements of array antenna, perfect magnetic conductor(PMC) and SOFT-surface is designed and located at center of ground plane, isolation and gain is simulated by commercial full wave simulator(HFSS). As a result, isolation of more than 40 dB and gain improvement of 2.2 dBi are obtained at E-plane array in case of both PMC and SOFT-surface. At H-plane array, air coupling is dominant compared to coupling by surface wave. It is conclude that this study is useful for design of compact array antenna and performance improvement of array antenna.Key words: Array Antenna, Surface Wave, Isolation, Perfect Magnetic Conductor(PMC), SOFT-Surface h7#ij[klmfn6o3p,qEr%s#t.uh7#2015v Q6(wx6)ypz#y{3p,qEr%s[|#fnt(No. 2015R1A6A1A03031833).u }~LwW*QF €ZI(Department of Electronic Information and Communication Engineering, Hongik University) *}~Lw‚ƒ„W*)*# o(Metamaterial Electronic Device Research Center, Hongik University)Manuscript received October 2, 2015 ; Revised December 1, 2015 ; Accepted February 12, 2016. (ID No. 20151002-17S)Corresponding Author: Jeong-Hae Lee (e-mail: jeonglee@hongik.ac.kr)

Antenna selection in a SIMO architecture for HF radio links

AbstractThis work takes place in the global design of a SIMO architecture (single input multiple output) for transhorizon radio links, aiming at a significant increase in the data rate when compared with standard modems based in general on a SISO scheme (single input single output). The project is subject to available space constraints at the receive end, involving mobile stations or onboard implementation. We consider solutions that appear as extensions of the compact and heterogeneous antenna array that we proposed previously: collocated antennas of different types are set up with the same phase center and present diversity in their polarization sensitivities to make array processing effective. Given the number NC of receive channels, we address the problem of selecting the most effective antennas in a set of NA possible candidates including monopoles, dipoles, loop antennas with various geometries, and orientations. The criterion to be maximized is the SIMO outage capacity, a quantity based on the statistical distribution of the SIMO Shannon capacity estimated for a large number of ionospheric channel realizations, each of them being quantified by its channel impulse response including the receive antenna directional responses. Results are presented in the context of a 1 × 2 SIMO structure: the identification of the two most effective antennas in a set of NA = 15 sensors indicates that the optimal structures involve two orthogonal horizontal dipoles or two vertical orthogonal loop antennas. In these conditions, the outage capacity reaches up to 2.23 bps/Hz, a value that significantly exceeds the performances of standard modems.

A Compact High-Performance Patch Antenna Array for 60-GHz Applications

In this letter, a compact and high-performance patch antenna array is developed for 60-GHz applications. The method to enhance both the gain and the frequency bandwidth of the antenna array simultaneously by using a parallel-series feed network together with the differential feeding technique is studied thoroughly. The tested antenna array achieves operation bandwidth ( ) from 55 to 68 GHz, which covers worldwide 60-GHz unlicensed band of 57-66 GHz, with peak gain of 12.8-15.6 dBi. The measured -3-dB beamwidths at 61.5 GHz are around ±13 ° in E-plane and ±15 ° in H-plane, respectively. The designed high-gain antenna array has a compact size of only 20 ×14 mm 2 excluding the connector footprint for test.

DESIGN AND ANALYSIS OF COMPACT 108 ELEMENT MULTIMODE ANTENNA ARRAY FOR MASSIVE MIMO BASE STATION

In this paper, we report the design and evaluation of a compact 108-element base station antenna array for massive multi-input multi-output (MIMO) system using a 3-port multimode antenna as a unit element. Of these three ports, port 1 and port 2 have orthogonally polarized broadside radiation pattern with measured peak gain of 6.5 dBi and impedance bandwidth of 254 MHz (2.268 GHz- 2.522 GHz) and 238 MHz (2.248 GHz-2.486 GHz), respectively, while port 3 has monopole-like radiation pattern having measured peak gain of 1.21 dBi and impedance bandwidth of 102 MHz (2.376 GHz- 2.478 GHz). Mutual coupling among all the ports is kept as less than �14 dB. Design of 108-element massive MIMO antenna array is evaluated as a base station antenna for multiuser urban street grid scenario in MIMO-OFDM downlink system, which is further modeled using Wireless World Initiative New Radio II (WINNER II) Channel models in MATLAB. Parameters like Singular value spread and Dirty Paper Coding (DPC) sum capacity was calculated and compared with i.i.d channel model. For 4 users case using same frequency and time resource, singular value spread and DPC sum capacity for presented antenna array converges to 7 dB and 11.6 bps/Hz at 10 dB SNR respectively.

Conception and optimisation of UWB microstrip array antennas for radar applications with ordinary end-fire beam steering characteristic

In this paper, a compact linear array antennas with ultra wideband (UWB) end-fire characteristic for radar applications is proposed. The array antenna consists of four rectangular antenna element with a partial ground plane and a coplanar waveguide (CPW) transmission line of 50 ohm. The proposed array antennas is etched onto a FR4 printed circuit board (PCB) with an overall size of 85 × 32 × 1.58 mm3 and a dielectric constant er = 4.4, it is planar and simple, and it is able to achieve an impedance bandwidth about 72% which is required in various radar applications like weather radars, local air traffic radars and naval radars. Ansoft's high frequency structure simulator (HFSS) and computer simulation tool (CST) softwares are used to calculate and compare the various parameters mentioned after.