Ultra-Wideband Phased Arrays for Small Mobile Platforms

This dissertation presents the development of a new class of Ultra-Wideband (UWB) apertures for aerial applications by introducing designs with over 50:1 bandwidth and novel differential feeding approaches. Designs that enable vertical integration for flip-chip millimeter-wave (UWB) transceivers are presented for small aerial platforms. Specifically, a new scalable tightly coupled array is introduced with differential feeding for chip integration. This new class of beam-forming arrays are fabricated and experimentally tested for validation with operation from as low as 130 MHz up to 18 GHz. A major achievement is the study of millimeter wave beamforming designs that operate from 22-80 GHz, fabricated using low-cost printed circuit board (PCB) methods. This low-cost fabrication approach and associated testing of the beamforming arrays are unique and game-changing

High Isolation Compact UWB MIMO Antennas

This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s11277-022-10083-8In this work, two elements and four elements compat UWB MIMO antennas are designed and fabaricted. A printed circular disc with five circular slots is selected in this work due to its UWB performance and compact size for the MIMO antenna system. CST software is used in the simulation process. Measured S parameters show that the MIMO antennas work well from 3 GHz up to 20 GHz (maximum working frequency of the measurent instrumnts). The two elements MIMO antenna has a size of 70×40 mm2 meanwhile the four elements MIMO antenna has a size of 70×70 mm2. Mesurement results show that the isolation among the antenna elemnts is higher than 20 dB. The Envelope Correlation Coefficient, Diversity Gain, Channel Capacity Loss, Mean Effective Gain and Total Active Reflection Coefficient are studied in this paper. Simultions results show that the MIMO atennas have a satsisfactory performance up to 50 GHz

Isolation Enhancement of Densely Packed Array Antennas with Periodic MTM-Photonic Bandgap for SAR and MIMO Systems

A metamaterial photonic bandgap (MTM-PBG) periodic structure is used as a decoupling frame to improve the isolation between transmit–receive (T/R) sections of densely packed array antenna in synthetic aperture radar (SAR) and multiple-input multiple-output (MIMO) systems. With this technique the MTM-PBG structure is shown to effectively suppress surface wave propagations between the T/R array antennas by an average of 12dB. MTM-PBG layer comprises a periodic arrangement of dielectric circles etched in the cross-shaped microstrip frame that is inserted between the radiating elements. Unlike other recently reported methods, the advantages of the proposed technique are:(i) simplicity; (ii) cost effectiveness as there is no need for short-circuited via-holes or 3D metal walls; and (iii) can be retrofitted in existing array antennas. The proposed T/R array antennas were designed to operate over an arbitrary frequency range (9.25-11GHz) with a fractional bandwidth (FBW) of 17.28%. With this technique (i) the side-lobes are reduced; (ii) there is minimal effect on the gain performance; and (iii) the minimum edge-to-edge gap between adjacent radiating elements can be reduced to 0.15at 9.25GHz

A Compact Band-Notched UWB MIMO Antenna with Enhanced Isolation Using Comb Shaped Decoupling Element

A compact 37mm × 26 mm two element multiple-input-multiple-output (MIMO) antenna is presented for ultra wide band (UWB) system application with band notched characteristics. The proposed antenna comprises two semi trapezoidal shaped monopole radiating elements. The band rejection feature around 3.5 GHz has been achieved by incorporating the open ended quarter wavelength spiral shaped slot resonator on the patched surface. In order to realize the enhanced isolation, comb shaped symmetrical stub arrangement are embedded at the U shaped etched periphery to the stepped ground plane between the monopole radiators. This novel design approach leads towards isolation enhancement better than 20 dB throughout the UWB spectral range (3.1 -10.6 GHz) with peak isolation near about 46 dB. The Envelope Correlation Coefficient is significantly lower than 0.005 in entire operating range except the WiMAX rejection band

(3.1-20) GHz MIMO Antennas

In this paper, a super-wideband (SWB) printed monopole antenna has been designed and manufactured. The measured frequency band in terms of reflection coefficient is from 3.1 to 20 GHz under a -10 dB criteria, thanks to the inclusion of a taper impedance adapter. This single antenna has been used to implement and analyze several MIMO antenna configurations, where the isolation between the compounding elements has been checked and optimized to improve the Envelope Correlation Coefficient. Two elements MIMO configurations (parallel ports or orthogonal diversity), as well as four element MIMO antennas with parallel ports are presented. Non continuous ground planes of the MIMO antenna elements with the inclusion of L shaped thin strips are proposed as valid structures to significantly improve the side by side mutual coupling from an initial peak value of 15 dB to better than 24 dB within the entire frequency band. In all the presented MIMO antenna structures, the measured values demonstrate good performance up to 20 GHz, both in reflection and isolation. Nevertheless, the influence of the mutual coupling effects has been checked as more significant in the lower part of the frequency band, especially in the 4 element MIMO configuration. The inclusion of the L shaped strips in the ground plane significantly mitigates this effect. Although the antennas have only been measured up to 20 GHz (upper frequency limit of the laboratory Vector Network Analyzer), simulations show satisfactory antennas’ performance up to 50 GHz

A Comprehensive Survey on 'Various Decoupling Mechanisms with Focus on Metamaterial and Metasurface Principles Applicable to SAR and MIMO Antenna Systems'

Nowadays synthetic aperture radar (SAR) and multiple-input-multiple-output (MIMO) antenna systems with the capability to radiate waves in more than one pattern and polarization are playing a key role in modern telecommunication and radar systems. This is possible with the use of antenna arrays as they offer advantages of high gain and beamforming capability, which can be utilized for controlling radiation pattern for electromagnetic (EM) interference immunity in wireless systems. However, with the growing demand for compact array antennas, the physical footprint of the arrays needs to be smaller and the consequent of this is severe degradation in the performance of the array resulting from strong mutual-coupling and crosstalk effects between adjacent radiating elements. This review presents a detailed systematic and theoretical study of various mutual-coupling suppression (decoupling) techniques with a strong focus on metamaterial (MTM) and metasurface (MTS) approaches. While the performance of systems employing antenna arrays can be enhanced by calibrating out the interferences digitally, however it is more efficient to apply decoupling techniques at the antenna itself. Previously various simple and cost-effective approaches have been demonstrated to effectively suppress unwanted mutual-coupling in arrays. Such techniques include the use of defected ground structure (DGS), parasitic or slot element, dielectric resonator antenna (DRA), complementary split-ring resonators (CSRR), decoupling networks, P.I.N or varactor diodes, electromagnetic bandgap (EBG) structures, etc. In this review, it is shown that the mutual-coupling reduction methods inspired By MTM and MTS concepts can provide a higher level of isolation between neighbouring radiating elements using easily realizable and cost-effective decoupling configurations that have negligible consequence on the arrays characteristics such as bandwidth, gain and radiation efficiency, and physical footprint

A Comprehensive Survey on “Various Decoupling Mechanisms With Focus on Metamaterial and Metasurface Principles Applicable to SAR and MIMO Antenna Systems”

Nowadays synthetic aperture radar (SAR) and multiple-input-multiple-output (MIMO) antenna systems with the capability to radiate waves in more than one pattern and polarization are playing a key role in modern telecommunication and radar systems. This is possible with the use of antenna arrays as they offer advantages of high gain and beamforming capability, which can be utilized for controlling radiation pattern for electromagnetic (EM) interference immunity in wireless systems. However, with the growing demand for compact array antennas, the physical footprint of the arrays needs to be smaller and the consequent of this is severe degradation in the performance of the array resulting from strong mutual-coupling and crosstalk effects between adjacent radiating elements. This review presents a detailed systematic and theoretical study of various mutual-coupling suppression (decoupling) techniques with a strong focus on metamaterial (MTM) and metasurface (MTS) approaches. While the performance of systems employing antenna arrays can be enhanced by calibrating out the interferences digitally, however it is more efficient to apply decoupling techniques at the antenna itself. Previously various simple and cost-effective approaches have been demonstrated to effectively suppress unwanted mutual-coupling in arrays. Such techniques include the use of defected ground structure (DGS), parasitic or slot element, dielectric resonator antenna (DRA), complementary split-ring resonators (CSRR), decoupling networks, P.I.N or varactor diodes, electromagnetic bandgap (EBG) structures, etc. In this review, it is shown that the mutual-coupling reduction methods inspired By MTM and MTS concepts can provide a higher level of isolation between neighbouring radiating elements using easily realizable and cost-effective decoupling configurations that have negligible consequence on the array’s characteristics such as bandwidth, gain and radiation efficiency, and physical footprint

Compact dual-band antenna based on CRLH-TL for WWAN/LTE terminal applications

In this article, a compact dual‐band antenna based on composite right/left‐handed transmission line (CRLH‐TL) is proposed for WWAN/LTE wireless terminal applications. By using 2 symmetrical CRLH structures, the proposed antenna can easily produce 2 wide separate operating frequency bands with a compact size of 25 × 25 × 6 mm3. Additionally, a pair of matching strips is introduced on both sides of the feeding line to further improve the impedance characteristics of the terminal antenna. The experimental results demonstrate the proposed antenna is capable of working over the frequency ranges of 0.66‐1.06 GHz and 1.68‐2.88 GHz with |S11| < −6 dB, which can cover the bands of LTE700, GSM850, GSM900, GSM1800, GSM1900, UMTS, LTE2300, and LTE2500 for wireless terminals. Moreover, the multiple input multiple output (MIMO) operating performance of the proposed antenna element is also studied, and an enhanced isolation between the antenna elements is obtained by utilizing the defected ground structures and grounded branches

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression