scholarly journals Recent Developments of Reconfigurable Antennas for Current and Future Wireless Communication Systems

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 128 ◽  
Author(s):  
Naser Ojaroudi Parchin ◽  
Haleh Jahanbakhsh Basherlou ◽  
Yasir Al-Yasir ◽  
Raed Abd-Alhameed ◽  
Ahmed Abdulkhaleq ◽  
...  

Reconfigurable antennas play important roles in smart and adaptive systems and are the subject of many research studies. They offer several advantages such as multifunctional capabilities, minimized volume requirements, low front-end processing efforts with no need for a filtering element, good isolation, and sufficient out-of-band rejection; these make them well suited for use in wireless applications such as fourth generation (4G) and fifth generation (5G) mobile terminals. With the use of active materials such as microelectromechanical systems (MEMS), varactor or p-i-n (PIN) diodes, an antenna’s characteristics can be changed through altering the current flow on the antenna structure. If an antenna is to be reconfigurable into many different states, it needs to have an adequate number of active elements. However, a large number of high-quality active elements increases cost, and necessitates complex biasing networks and control circuitry. We review some recently proposed reconfigurable antenna designs suitable for use in wireless communications such as cognitive-ratio (CR), multiple-input multiple-output (MIMO), ultra-wideband (UWB), and 4G/5G mobile terminals. Several examples of antennas with different reconfigurability functions are analyzed and their performances are compared. Characteristics and fundamental properties of reconfigurable antennas with single and multiple reconfigurability modes are investigated.

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2184
Author(s):  
Sriram Arumugam ◽  
Sangeetha Manoharan ◽  
Sandeep Kumar Palaniswamy ◽  
Sachin Kumar

This paper presents the design and analysis of a planar ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna for modern vehicular communication systems. The proposed unit cell antenna structure was designed using modified elliptical radiators on a Rogers RO3003 substrate, has a size of 22 × 22 × 0.76 mm3, and covers an impedance bandwidth (S11 ≤ −10 dB) of 3.14 GHz to 12.24 GHz. The peak gain and efficiency of the unit cell prototype are 5.1 dBi and 81%, respectively. The unit cell was further developed into a MIMO antenna configuration with four elements placed orthogonal to each other in a single plane measuring 50 × 50 × 0.76 mm3. The measured isolation between the antenna elements was greater than 20 dB. The measured envelope correlation coefficient (ECC) of the MIMO antenna was less than 0.004, the diversity gain (DG) was greater than 9.67 dB, the total active reflection coefficient (TARC) was <−10 dB, and the mean effective gain (MEG) ratio was > 0.99. The characteristics of the proposed unit cell and the MIMO antenna were investigated for housing effects in order to validate the consistent performance of the antenna in the presence of conducting bodies. In addition, the radiation characteristics of the antenna when mounted on a vehicle were analyzed using a virtual model of the car. The results show that the proposed quad-element UWB MIMO array is compact, has good performance, and is well-suited for automotive applications.


2011 ◽  
Vol 57 (1) ◽  
pp. 91-96
Author(s):  
Giennadij Czawka ◽  
Marek Garbaruk

Matrix Analysis and Pulse Transmission of Antenna Array for MIMO UWB Systems This paper presents a theoretical matrix analysis of antenna structure consisting of two double-element planar antennas for ultra-wideband (UWB) application in 2*2 MIMO indoor communication systems. The structure and characteristics of pla-nar two-element UWB antenna are presented. Two matrix models of MIMO antenna system are represented in the paper. A stan-dard MIMO signal transmission matrix without taking into con-sideration the coupling between antennas is described. A new ap-proach to a full electromagnetic analysis based on the scattering matrix of the MIMO spatial antenna array is proposed. Func-tional power parameters for the whole MIMO UWB transmit-receive antenna structure are introduced. Results of computer si-mulations of different matrices describing a MIMO antenna sys-tem and the transmission propagation pulses are presented.


2009 ◽  
Vol 1 (6) ◽  
pp. 461-468 ◽  
Author(s):  
Walid El Hajj ◽  
François Gallée ◽  
Christian Person

A new model of two-access reconfigurable antennas for future mobile communication systems is presented in this article. This structure is based on a slot antenna with two separated access ports, isolated and matched at 1 and 2 GHz, respectively. The novelty of this element lies in the fact that first a filtering structure is integrated in the antenna, and then any additional switching or frequency path selecting components that would induce losses and noise degradation is suppressed. Such flexible structures are assumed to be used in a future opportunistic radio, incorporating special features of “spectrum sensing”. The concept of the antenna illustrated by simulation and measurement is presented.


Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1476
Author(s):  
Tathababu Addepalli ◽  
Arpan Desai ◽  
Issa Elfergani ◽  
N. Anveshkumar ◽  
Jayshri Kulkarni ◽  
...  

Multiple-input multiple-output (MIMO) antennas with four and eight elements having connected grounds are designed for ultra-wideband applications. Careful optimization of the lines connecting the grounds leads to reduced mutual coupling amongst the radiating patches. The proposed antenna has a modified substrate geometry and comprises a circular arc-shaped conductive element on the top with the modified ground plane geometry. Polarization diversity and isolation are achieved by replicating the elements orthogonally forming a plus shape antenna structure. The modified ground plane consists of an inverted L strip and semi ellipse slot over the partial ground that helps the antenna in achieving effective wide bandwidth spanning from (117.91%) 2.84–11 GHz. Both 4/8-port antenna achieves a size of 0.61 λ × 0.61 λ mm2 (lowest frequency) where 4-port antenna is printed on FR4 substrate. The 4-port UWB MIMO antenna attains wide impedance bandwidth, Omni-directional pattern, isolation >15 dB, ECC < 0.015, and average gain >4.5 dB making the MIMO antenna suitable for portable UWB applications. Four element antenna structure is further extended to 8-element configuration with the connected ground where the decent value of IBW, isolation, and ECC is achieved.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Minghuan Wang ◽  
Jingchang Nan ◽  
Jing Liu

A miniaturized ultra-wideband multiple-input multiple-output (UWB MIMO) two-port antenna with high isolation based on FR4 is designed in this article. The size of the antenna is only 18 × 28 × 1.6 mm3. The MIMO antenna consists of two identical antenna elements symmetrically placed on the same dielectric substrate in opposite directions. By loading three crossed X-shaped stubs between two unconnected ground planes, high isolation and good impedance matching are achieved. The working frequency band measured by this UWB MIMO antenna is 1.9–14 GHz, and the isolation is kept above 20.2 dB in the whole analysis frequency band. Good radiation characteristics as well as envelope correlation coefficient (ECC, <0.09), mean effective gain (MEG), and channel capacity loss (CCL) in the passband meet the requirements of the application, which can be applied to the UWB wireless communication system. To verify the applicability of the proposed method for enhancing the isolation between antenna elements, the two-port antenna structure was extended to a four-port antenna structure. In the case of loading the X-shaped stubs to connect to the ground plane, the isolation of the antenna is maintained above 15.5 dB within 1.7–14 GHz.


Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 336 ◽  
Author(s):  
Naser Ojaroudi Parchin ◽  
Haleh Jahanbakhsh Basherlou ◽  
Yasir I. A. Al-Yasir ◽  
Ahmed M. Abdulkhaleq ◽  
Raed A. Abd-Alhameed

Due to the fast development of wireless communication technology, reconfigurable antennas with multimode and cognitive radio operation in modern wireless applications with a high-data rate have drawn very close attention from researchers. Reconfigurable antennas can provide various functions in operating frequency, beam pattern, polarization, etc. The dynamic tuning can be achieved by manipulating a certain switching mechanism through controlling electronic, mechanical, physical or optical switches. Among them, electronic switches are the most popular in constituting reconfigurable antennas due to their efficiency, reliability and ease of integrating with microwave circuitry. In this paper, we review different implementation techniques for reconfigurable antennas. Different types of effective implementation techniques have been investigated to be used in various wireless communication systems such as satellite, multiple-input multiple-output (MIMO), mobile terminals and cognitive radio communications. Characteristics and fundamental properties of the reconfigurable antennas are investigated.


Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 456 ◽  
Author(s):  
Naser Ojaroudi Parchin ◽  
Haleh Jahanbakhsh Basherlou ◽  
Yasir I. A. Al-Yasir ◽  
Atta Ullah ◽  
Raed A. Abd-Alhameed ◽  
...  

In this study, we propose a design of a multi-band slot antenna array applicable for fourth-generation (4G) and fifth-generation (5G) smartphones. The design is composed of double-element square-ring slot radiators fed by microstrip-line structures for easy integration with radio frequency (RF)/microwave circuitry. The slot radiators are located on the corners of the smartphone printed circuit board (PCB) with an overall dimension of 75 × 150 mm2. The proposed multiple-input multiple-output (MIMO) antenna is designed to meet the requirements of 4G and 5G mobile terminals with essential bandwidth for higher data rate applications. For −10 dB impedance bandwidth, each single-element of the proposed MIMO design can cover the frequency ranges of 2.5–2.7 GHz (long-term evolution (LTE) 2600), 3.45–3.8 GHz (LTE bands 42/43), and 5.00–5.45 GHz (LTE band 46). However, for −6 dB impedance bandwidth, the radiation elements cover the frequency ranges of 2.45–2.82 GHz, 3.35–4.00 GHz, and 4.93–5.73 GHz. By employing the microstrip feed lines at the four different sides of smartphone PCB, the isolation of the radiators has been enhanced and shows better than 17 dB isolation levels over all operational bands. The MIMO antenna is implemented on an FR-4 dielectric and provides good properties including S-parameters, efficiency, and radiation pattern coverage. The performance of the antenna is validated by measurements of the prototype. The simulation results for user-hand/user-head impacts and specific absorption rate (SAR) levels of the antenna are discussed, and good results are achieved. In addition, the antenna elements have the potential to be used as 8-element/dual-polarized resonators.


Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sachin Kumar Yadav ◽  
Amanpreet Kaur ◽  
Rajesh Khanna

Abstract In this article, cross-shaped metallic parasitic strips based two radiator element multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) is excited by quadrature wave transformer microstrip feedline, designed, simulated and fabricated for ultra-wideband (UWB) applications. The proposed MIMO antenna structure is implemented with the help of two rectangular-shaped radiator elements that supports three modes HE11δ , HE21δ , and HE12δ at 4.4, 8.3, 10.8 GHz respectively. These fundamental and higher-order modes are supported to wide impedance bandwidth. Inverted T-shaped metallic strip and ground stub to improve the impedance bandwidth 104.6% (3.3–10.8 GHz) with 5.7 dBi peak gain, to enhance the coupling coefficient by stub, scissor-shaped defected ground structure and cross-shaped metallic parasitic strips are used in the existed structure. The MIMO diversity parameters are implemented as simulated ECC ≤ 0.003, DG ≥ 9.98 dB, and CCL ≤ 0.68. All the obtained MIMO antenna parameters are within the acceptable limit for providing high data rate for UWB applications.


Author(s):  
Anirban Karmakar ◽  
Anuradha Saha

A novel compact ultra-wideband (UWB) multiple-input multiple-output (MIMO) slot antenna with band notch characteristics is presented for portable wireless UWB applications. The antenna comprises of co-planar waveguide feed (CPW) and two radiating monopoles oriented in orthogonal orientation for providing orthogonal radiation patterns. A Minkowski fractal parasitic stub along with a Minkowski fractal grounded stub has been placed at 45° between the monopoles to reduce the coupling between them, which in turn establishes high isolation between the radiators. An excellent band notch characteristic is obtained at 5.5 GHz by etching a modified E-shaped compact slot on the radiators. Results show that the designed antenna meets -10 dB impedance bandwidth and -17 dB isolation throughout the entire operating band (3.1 -12 GHz). Novelty of this design lies in improving isolation using fractal which occupies less space in compared to other isolation mechanisms in MIMO structures. The simulated and measured results depict that the proposed antenna is convenient for MIMO diversity systems.


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