scholarly journals Ultra-Wideband MIMO Array for Penetrating Lunar Regolith Structures on the Chang’e-5 Lander

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 8
Author(s):  
Wei Lu ◽  
Yuxi Li ◽  
Yicai Ji ◽  
Chuanjun Tang ◽  
Bin Zhou ◽  
...  

The Chang’e-5 lunar exploration mission of China is equipped with a Lunar Regolith Penetrating Radar (LRPR) for measuring the thickness and structures of the lunar regolith in the landing area. Since the LRPR is stationary, an ultra-wideband multiple-input multiple-output (MIMO) array is designed as a replacement for conventional mobile subsurface probing systems. The MIMO array, with 12 antenna elements and a switch matrix, operates in the frequency band from 1.0 to 4.75 GHz. In this work, the design and layout of the antenna elements were optimized with respect to the lander. To this end, the antenna elements were designed as miniaturized Vivaldi antennas with quarter elliptical slots (i.e., quarter elliptical slotted antenna, or QESA). QESAs are significantly small while being able to mitigate the impact of the lander on antenna electrical performances. QESAs also have a wide operating bandwidth, flat gain, and excellent time domain characteristics. In addition, a high-temperature resistant ultra-light radome with high transmissivity is designed to protect the external antenna array. After calibration, the MIMO array is used to detect targets embedded in volcanic ash. The detection depth reaches 2.5 m, and the detection effect is good.

Author(s):  
M. Saravanan ◽  
R. Kalidoss ◽  
B. Partibane ◽  
K. S. Vishvaksenan

Abstract The design, analysis, fabrication, and testing of a four-port multiple-input multiple-output (MIMO) antenna is reported in this paper for automotive communications. The MIMO antenna is constructed using the basic antenna element exploiting a slot geometry. Two such antennas are developed on the same microwave laminate to develop a two-port MIMO antenna. Two such microwave laminates are interlocked to create the four-port MIMO scheme. The most distinct feature of the proposed architecture is that the inter-port isolation is well-taken care without the need for an external decoupling unit. The four-port MIMO antenna has an overall volume of 32 × 15 × 32 mm3. The prototype MIMO antenna is fabricated and the measurements are carried out to validate the simulation results. The antenna offers ultra-wideband (UWB) characteristics covering the frequency range of 2.8–9.5 GHz. The average boresight gain of the antenna ranges from 3.2 to 5.41 dBi with the peak gain at 8 GHz. The simulated efficiency of the antenna is greater than 73% within the operating bandwidth. The MIMO parameters such as envelope correlation coefficient, diversity gain, and mean effective gain are evaluated and presented. The appropriateness of the proposed antenna for deployment in the shark fin housing of the present-day automobiles is verified using on-car performance estimation.


Circuit World ◽  
2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Premalatha J. ◽  
Sheela D.

Purpose This paper aims to present the design of a compact vertically polarized four-element UWB antenna suitable for MIMO communications. Design/methodology/approach The unit cell antenna is constructed using a square ring radiator excited through a stepped impedance feed. The proposed antenna covers the Ultra-wideband (UWB) spectrum ranging from 2.2 to 12.3 GHz. The isolation between the unit cell antennas in the array is enhanced using a simple microstrip line resonator. The decoupling element is connected to the ground through a via. Findings The proposed scheme offers at least 16 dB improvement in the port-to-port coupling. Furthermore, the four-element antenna array is constructed using a specific interlocking scheme. The proposed antenna array’s Multiple Input Multiple Output (MIMO) performance metrics are analyzed. Originality/value By suitably selecting the excitation port, directional radiation patterns can be realized. The combined radiation pattern covers 360 degrees. A prototype antenna array is fabricated, and the simulation results are verified using real-time experiments. The proposed antenna is a suitable candidate for shark fin housing in automotive communications.


Author(s):  
Muhammad Saeed Khan ◽  
Antonio-D. Capobianco ◽  
Sajid Asif ◽  
Adnan Iftikhar ◽  
Benjamin D. Braaten ◽  
...  

2009 ◽  
Vol 18 (06) ◽  
pp. 1075-1080
Author(s):  
ZHIQUAN BAI ◽  
YUANQUAN XU ◽  
XIAOTONG LI ◽  
RONGKAI LI ◽  
DONGFENG YUAN ◽  
...  

In this paper, we investigate the multiple input multiple output (MIMO) direct sequence bipolar pulse amplitude modulation (DS-BPAM) ultra wideband (UWB) system over indoor multipath fading channels based on the research of Alamouti space-time block codes (STBC) and DS-BPAM UWB system. Selective Rake (SRake) receiver is employed in this paper in order to deal with the multipath effects. Theoretical bit error probability of the MIMO DS-BPAM UWB system with SRake receiver is derived. Simulation results of the MIMO DS-BPAM UWB system with SRake receiver and conventional coherent receiver over multipath fading channels are provided. The results show the efficiency of the MIMO DS-BPAM UWB system with SRake receiver.


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