Path loss compensated millimeter wave antenna module integrated with 3D‐printed radome

Millimeter wave antennas designed at 28 GHz is essential for future 5G base stations or access points and mobile terminals. In this paper, a compact pattern diversity module for millimeter wave 5G base stations is proposed by using 3D‐printing for radome design. In order to achieve path loss compensation in an indoor base station context, the gains of the antennas radiating at ±45° must be 3 dB higher than the antenna radiating in the boresight axis. First, an inset fed patch antenna integrated with a low‐cost industry standard 3D‐printed superstrate with Polylactic acid (PLA) is investigated to study its radiation characteristics. The radome is designed in such a way for optimal gain enhancement with minimal physical footprint. The height of the 2 mm thick superstrate is optimized for a boresight gain of 8 dBi. Second, the 3D‐printed superstrate is optimized for a boresight gain of 11 dBi, which satisfies the criterion of path loss compensation, in this case the antenna achieves an aperture efficiency of close to 72% at 28 GHz. A compact pattern diversity module with customized 3D‐printed radome is also presented to achieve path loss compensation and wide angular coverage of ±70° with associated isolation of less than 35 dB across the ports and the band. Detailed simulation and measurement results are presented.     

Design of miniaturized D‐band dual‐polarized dipole base station antenna based on coupling feeding

This article designs a coupling feeding miniaturized base station antenna. This base station antenna works in D‐band (2500‐2700 MHz). By introducing a bending structure to increase the current path of the dipole, the overall size of the dipole antenna can be reduced. The final design of antenna element size is only 36.8 × 36.8 mm² (0.32 × 0.32λ²). The simulation results show that the return loss of the two ports is greater than 23 dB, the isolation between the two ports is greater than 29 dB, the half‐power beamwidth of the antenna is 63° ± 1.5°, and the gain is greater than 9 dBi. The physical processing and simulation results are basically consistent, which prove the practicability of the dipole antenna. A broadband dipole antenna and this antenna are selected for array analysis. When it works in D‐band, the isolation of the antenna element designed in this article is better than that of the broadband dipole antenna.     

Millimeter‐wave antenna with wide‐scan angle radiation characteristics for MIMO applications

A three‐element quasi Yagi‐Uda antenna array with printed metamaterial surface generated from the array of uniplanar capacitively loaded loop (CLL) unit‐cells printed on the substrate operating in the band 25‐30 GHz is proposed. The metamaterial surface is configured to provide a high‐refractive index to tilt the electromagnetic (EM) beam from the two dipole antennas placed opposite to each other. The metamaterial region focuses the rays from the dipole antenna and hence increases the gain of the individual antennas by about 5 dBi. The antenna elements are printed on a 10 mil substrate with a center to center separation of about 0.5 λ ₀ at 28 GHz. The three‐element antenna covers 25‐30 GHz band with measured return loss of 10 dB and isolation greater than 15 dB between all the three ports. The measured gain of about 11 dBi is achieved for all the antenna elements. The three antenna elements radiate in three different directions and cover a radiation scan angle of 64°.     

A Dual‐band and dual‐polarized antenna array for 2G/3G/LTE base stations

A dual‐band antenna array is proposed for the application of base station (BS) in 2G/3G/long term evaluation (LTE) mobile communications. This antenna consists of two independent ±45° dual‐polarized arrays, one of which operates from 1.71 to 2.17 GHz, and the other of which is designed from 2.5 to 2.69 GHz. The proposed BS antenna array has a high isolation of greater than 29 dB and high front‐to‐back ratio of more than 26 dB at the operating frequencies. The measured peak gain is 17.9 and 18.1 dBi for the lower and upper bands, respectively, and the cross polarizations isolation (CPI)(within ±60º of the mainlobe) is 16 dB lower than the broadside co‐polarization. It was confirmed that the proposed antenna array meets the communication standards in China. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:154–163, 2016.     

Ten switched‐beams with 2 × 2 series‐fed 2.4 GHz array antenna and a simple beam‐switching network

This article presents a 2 × 2 series fed 2.4 GHz patch antenna array having multiple beam switching capabilities by using two simple 3 dB/90° couplers to achieve required amplitude and phase excitations for array elements with reduced complexity, cost and size. The beam switching performance with consistent gain and low side lobe levels (SLL) is achieved by exciting the array elements from orthogonally placed thin quarter‐wave (λ_g/4) feeds. The implemented array is capable to generate ten (10) switched‐beams in 2‐D space when series fed elements are excited from respective ports through 3 dB quadrature couplers. The dual polarized characteristics of presented array provide intrinsic interport isolation between perpendicularly placed ports through polarization diversity to achieve independent beam switching capabilities for intended directions. The implemented antenna array on 1.575 mm thick low loss (tan δ = 0.003) NH9450 substrate with ε_r = 4.5 ± 0.10 provides 10 dB return loss impedance bandwidth of more than 50 MHz. The measured beam switching loss is around 0.8 dB for beams switched at θ = ±20°, Ф = 0°, 90°, and 45° with average peak gain of 9.5 dBi and SLL ≤ ?10 dB in all cases. The novelty of this work is the capability of generating ten dual polarized switched‐beams by using only two 3 dB/90° couplers as beam controllers.     

Ka‐band phased patch array antenna integrated with a PET‐controlled phase shifter

In this article, a 4 × 4 linear‐phased patch array antenna, consisting of four 1 × 4 patch subarrays and a true time‐delay multiline phase shifter, is proposed on a thin film liquid crystal polymer substrate at Ka‐band. The patch antenna is designed with a gain of 6 dBi at 35 GHz and a bandwidth of 23% centered at 35 GHz. To enhance the gain and symmetrize the beam patterns of the 4 × 4 array, a 1 × 4 patch subarray in the E‐plane was designed and characterized. The subarray produces an enhanced gain of 11 dBi and a wide beamwidth of ±38° in the H‐plane for beam steering. The proposed phase shifter comprises a 1 × 4 microstrip line power splitter and a piezoelectric transducer‐controlled phase perturber. A large phase variation of up to 370° and a low insertion loss of less than 2 dB were demonstrated for the phase shifter at Ka‐band. The integrated phased array attains a gain of 15.6 dBi, and a continuous true‐time delay beam steering of up to 33 ± 1° from 31 to 39 GHz. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:199–208, 2016.     

Meander line MIMO antenna for 5.8 GHz WLAN application

A four port compact low profile planar MIMO antenna with meander line radiators and with polarization diversity effect has been proposed to cover 5.8 GHz wireless local area network application. The proposed MIMO antenna has ?10 dB impedance bandwidth of 1.4 GHz (5.3–6.7 GHz) along with the compact size of 38 × 38 mm² and an envelope correlation coefficient (ECC) of less than 4 × 10^?4 in the whole band. The proposed antenna resonates at 5.8 GHz frequency, having return loss of ?43.2 dB. The isolation between diagonal and opposite ports is more than 10 and 12 dB, respectively, in the presented frequency band. The total active reflection coefficient frequency response shows more than 1.0 GHz of bandwidth in the whole band. The antenna gain is more than 4.0 dBi in the operating frequency band. The radiating elements are very close to each other to make the design very compact.     

Wideband microstrip‐fed tapered slot antennas and phased array

Two wideband tapered slot antennas are designed, fabricated, and tested. The first antenna, which is fabricated on a high dielectric constant substrate (?_r = 10.2), shows a measured return loss of better than 10 dB from 1.6 to 12.4 GHz (7.7:1 bandwidth), and an antenna gain varying from 3.6 to 7.8 dBi. The second antenna is built on a low dielectric constant substrate (?_r = 2.2), and demonstrates return loss of better than 10 dB from 1.8 to 15.2 GHz (8.4:1 bandwidth). The second antenna also has improved antenna gain, from 5 to 15.6 dBi, and is used to build a wideband 1 × 4 H‐plane phased array with a total gain of 9–17 dBi and a beam steering angle of ±15° from 3 to 12 GHz. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

Circularly polarized high efficiency wideband reflectarray using rectangle‐shaped patch element

A single‐layer circularly polarized reflectarray using rectangle‐shaped elements in X‐band is presented in this article. The designed element is analyzed and optimized with parametrical studies to obtain good performance at the operating frequency. The phase shifts can be controlled by varying the dimensions in two orthogonal directions of the element for circular polarization. A reflectarray antenna with 27 × 27 elements has been designed, manufactured and measured. The measured results show that the proposed reflectarray antenna provides a 1‐dB gain bandwidth of 18% and a 3‐dB axial ratio of 13%. The measured peak gain at 10 GHz is 26.1 dBi, which corresponds to the high aperture efficiency of 40.3%.     

Broadband planar dipole array Antenna with double C‐shaped slit elements for digital TV broadcasting transmission

This research has proposed a planar rectangular dipole antenna enclosed in double C‐shaped parasitically slit elements (i.e., radiator element) on a double‐cornered reflector for bandwidth enhancement. In the study, simulations were first carried out to determine the optimal parameters of the radiator element and then a radiator element prototype was fabricated and mounted onto a double‐cornered aluminum reflector. The simulated and measured |S₁₁|<–10 dB of the antenna element covered the frequency ranges of 451–901 MHz (66.6%) and 455–886 MHz (64.3%), respectively. The gain was enhanced by the subsequent deployment of multiple radiator elements to fabricate a four‐element vertically array antenna on an elongated double‐cornered reflector. The simulated and measured |S₁₁|20 and 相似文献   

A 60‐GHz on‐chip slot‐array antenna in integrated‐passive‐device technology for antenna‐in‐package applications

A new millimeter‐wave antenna structure on a low‐cost, production platform integrated passive device technology is presented. The antenna consists of a 2‐by‐1 array of slot antennas at 60 GHz. An in‐house developed on‐chip antenna measurement setup was used to characterize the fabricated antenna. The measurement results show an antenna gain of more than 5 dBi with a return loss of 18 dB at 60 GHz. The better‐than‐10‐dB impedance bandwidth of the antenna covers the 60‐GHz unlicensed band from 57 to 64 GHz. The 3‐dB beamwidths of the antenna are 105° and 76° at E‐plane and H‐plane at 60 GHz, respectively. The size of the die of the antenna is 2 mm × 4.5 mm. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:155–160, 2014.     

High‐gain dual‐polarized antenna for ultrawideband applications

In this article, a high‐gain and dual‐polarized antenna with UWB operation is proposed. The antenna is composed of two tapered dipoles as radiating elements, which are arranged orthogonally and fed perpendicularly to achieve polarization diversity. A metallic cavity reflector is placed behind the radiator for high gain radiation entire the operating bandwidth. To validate the design method, an antenna prototype is designed, fabricated, and measured. The measured results demonstrate that the proposed design has good performance with |S₁₁| ≤ ?10 dB and isolation ≥20 dB over a frequency band 3.2‐8.8 GHz, equivalently to about 93.3%. In addition, unidirectional radiation pattern and broadside gain of from 8.1 to 11.8 dBi are obtained across the operating bandwidth.     

Microstrip tapered traveling wave antenna for wide range of beam scanning in X‐ and Ku‐bands

In this work, a broadband traveling wave antenna (TWA) is presented as a microstrip design that is capable of a wide range of beam scanning by changing the operation frequency within 8 to 14 GHz. For this purpose, a rhombus shaped microstrip patch is used as a unit element and TWA is built as a tapered microstrip line consisting of the cascaded rhombus shaped unit elements and terminated by a rectangular antenna instead of traditional resistive termination which can be called patch loaded traveling wave antenna (PLTWA). Optimization and simulation of the PLTWA is carried out using 3‐D Microwave simulation software CST and its dimensions are resulted as 130 × 30 mm. From the simulations, it should be noted that the patch termination increases the maximum gain almost 3 dB and the total efficiency up to 90% compared to the traditional resistive load over the operation band at the expanse of a small distortion on S₁₁ characteristics. Then the PLTWA is fabricated and measured along its operation band 8 to 14 GHz and it exhibits a peak gain of 9.5 dBi at 11 GHz. The measured gain of the proposed antenna is found between 9 dB and 12 dB and its beam direction is steerable with the range of 80° (?65°‐15°) over the operation band 8 to 14°GHz.     

A novel computational intelligence method for broadband dual-polarized base station antenna design

Broadband dual-polarized base station antenna requires wide impedance matching bandwidth, high-polarization isolation, stable radiation patterns, small gain variations, and high-cross polarization discrimination level. For antenna designers, it usually takes much computational time to design broadband base station antenna because there are extensive structural parameter analysis and multiple performance characteristics to be synthesized one by one. In this paper, a novel population-based computational intelligence optimization method is proposed for broadband base station antenna design. The proposed optimization method is based on self-adaptive weight vector strategy and could speedup searching through adjusting weight vectors and decreasing the number of full-time objective function evaluations. To verify its high efficiency of the proposed optimization method, a compact broadband dual-polarized base station antenna operating at 3.3–5.0 GHz is designed. From measurement results, it is observed that polarization isolation is higher than 27 dB, gain variation is smaller than 0.4 dB, and half-power beamwidth (HPBW) is within 65° ± 3°. In addition, XPD level is better than 24 dB at boresight direction and better than 13 dB within a sector of ±60°. Therefore, the designed antenna is promising for 5G broadband cellular base station applications.     

Compact ultrathin linear graded index metasurface lens for beam steering and gain enhancement

In this article, designing of a low‐profile planar linear graded index metasurface (LGIMS) lens is presented. A wide‐beam steerable high‐gain low‐profile antenna is designed by placing LGIMS over microstrip patch antenna radiator at an optimum height. Direction control of the radiation pattern of the microwave radiator by using amplitude and phase modulated metasurface is achieved. The measured peak gain of 13.50 dBi at an operating frequency of 10.08 GHz with progressively beam steering characteristic and progressive enhanced gain within a large conical region of apex angle 64°. The measured maximum gain tolerance of 2.43 dB with significantly reduced side lobe level is obtained by mechanically moving the ultrathin LGIMS lens along the negative parallel radiator axis. The mechanical movement of LGIMS lens over radiator results in to beam steering up to +32°. A maximum measured gain enhancement of 8.75 dB is achieved. The positive parallel radiator axis movement of LGIMS causes gradual broadside gain enhancement with maximum gain enhancement of 1.5 dB. The measured results are in good agreement with the simulated results.     

A K/Ka‐band dielectric and metallic 3D printed aperture shared multibeam parabolic reflector antenna for satellite communication

A K/Ka‐band (22‐33 GHz) high‐gain aperture shared multibeam parabolic reflector antenna is proposed. It performs a two‐dimensional beam scanning from a shared single parabolic reflector by introducing off‐focal feeds. The feed array is placed on and off the focal of the parabolic reflector. Traditionally, the feed blockage has a great impact on the performance of the antenna, which reduces the gain and increases the sidelobe level. The purpose of this paper is to suppress the negative effects of feed blockage by using hybrid material processing method. Both dielectric and metallic 3D printing technologies are used for antenna fabrication. The parabolic reflector antenna is printed by selective laser melting using aluminum alloy. The feed array and the supporting structures are printed by stereolithography apparatus in resin to control the blockage. The method helps to suppress the sidelobe level from ?10 to ?15 dB and to enhance gain by up to 2.3 dBi. The reflection coefficient is less than ?10 dB, while the coupling coefficient between the ports is less than ?20 dB over the entire designed band. At 31.5 GHz, the simulated maximum gain of the antenna are 30.7, 29.1, and 29.7 dBi, when different port separately excites. Multiple beams at ±15° and 0° are observed on both E‐ and H‐planes. Besides, it also verifies the possibility to use dielectric and metallic 3D printing technologies in hybrid for microwave device fabrication.     

A compact UWB MIMO antenna with neutralization line for WLAN/ISM/mobile applications

A novel design of 2 × 2 multiple‐input‐multiple‐output (MIMO) antenna is reported for ultra‐wideband applications. The neutralization line is implemented to minimize the mutual coupling between the radiating patches. The overall dimension of the designed antenna is 21 × 34 × 1.6 mm³. This antenna covers the measured bandwidth of 95.0% (3.52‐9.89 GHz) with better isolation (≤?22 dB) over the entire operating frequency band. The measured gain varies from 3.08 to 5.12 dBi over the entire band. The various antenna parameters such as S‐parameters, gain, efficiency, envelope correlation coefficient, mean effective gain, channel capacity loss, total active reflection coefficient, and radiation patterns are calculated and corresponding results are validated with the measured results.     

Enhancing characteristics of dual‐polarized BTS element antenna using metal director

This article proposes a dual‐polarized antenna with enhanced characteristics using metal director for base transceiver station applications. The proposed antenna consists of a main radiation element, ±45^? dual‐polarized feed structure, a reflector and a metal director. The metal director improves the impedance matching and increases the gain and front to back ratio. A prototype of the antenna is fabricated and the measured results show the wide frequency bandwidths of 63% for port 1 with frequency range 1.6 to 3.1 GHz and 60% for port 2 with frequency range 1.6 to 3 GHz. The obtained experimental isolation between ports is greater than 28 dB. The measured results also represent a gain of >8.4 dBi and the stable radiation patterns with half‐power beam width wider than of 65°. According to mentioned experimental results, the presented antenna can be used in the microcell base stations for Global System for Mobile, Code Division Multiple Access, and Long‐Term Evolution services.     

A wideband planar magneto‐electric tapered slot antenna with wide beamwidth

In this article, a wideband planar magneto‐electric (ME) tapered slot antenna (TSA) with wide beamwidth both in the E‐plane and H‐plane is investigated. By simply etching slots on the basic TSA, which can function as a combination of magnetic dipole and electric dipole, stable unidirectional patterns with wide beamwidth are obtained. The metal ground plane is further modified to realize wide beamwidth across a wide frequency bandwidth. Moreover, a double‐layer structure is employed to suppress the cross polarization. The measured results show that the proposed antenna can achieve an impedance bandwidth of 51.7% (7.22‐12.25 GHz) with a stable gain of 2.3 dBi, and a pattern bandwidth of 43% (7.8‐12.2GHz) for more than 135° half‐power beamwidth. The measured front‐to‐back (F/B) ratio is more than 15 dB in the pattern bandwidth.     

Design of dual‐band microstrip patch antenna with right‐angle triangular aperture slot for energy transfer application

This work focusing on the dual‐band antenna design with rectifying circuit for energy transfer system technology for enhancement gain performance. The air gap technique is applied on this microstrip antenna design work to enhance the antenna gain. The work begins with designing and analyzing the antenna via the CST Microwave Studio software. After validation on acceptable performance in simulation side is obtained, the return loss, S₁₁ of the antenna is measured using vector network analyzer equipment. The rectifier circuit is used to convert the captured signal to DC voltage. This projected dual‐band antenna has successfully accomplished the target on return loss of ?44.707 dB and ?32.163 dB at dual resonant frequencies for 1.8 GHz and 2.4 GHz, respectively. This proposed antenna design benefits in low cost fabrication and has achieved high gain of 6.31 dBi and 7.82 dBi for dual‐band functioning frequencies.