EBG/SNG Integrated Antenna System with Improved Mutual Isolation For 5G Wireless Systems

Recent wireless communication systems are mostly based on multiple antennas to satisfy the reliability, gain, and bandwidth requirements. These wireless systems include multiple-input and multiple-output (MIMO) systems and antenna arrays. In MIMO, multiple antennas are used to simultaneously send and receive data stream in a multipath environment, whereas array configuration of antenna elements is often required to achieve high gain and reconfigurable properties. Due to the limited size of the hand-held devices, multiple antenna elements need to be packed in a close-proximity at the cost of antenna-gain and mutual interference. Thus, improving isolation between the antennas used for cellular communication, global positioning, WIFI, near field communications is essential to maintain channel capacity and reliability. Popular techniques employed to improve antennas isolation include; parasitic elements, frequency selective surfaces, decoupling networks, neutralization lines, metamaterials, etc. Although these techniques can reduce the isolation of antenna elements up to a desired level, recent miniaturization of hand-held devices demands further reduction in the mutual coupling due to ever reducing the size of the system boards. In this project, electromagnetic coupling between printed antenna elements, placed at a distance lower than 1/2 free space wavelength, are considerably reduced using novel two techniques that employ electromagnetic bandgap structure (EBG) and single negative material (SNG). The first technique employs EBG structure printed on the antenna substrate to filter out the interfering signals between the neighboring antennas due to the surface waves. The second technique integrates SNG material, represented by 2D arrangement of periodic structure, within the antennas common ground plane to suppress the induced surface current flowing between neighboring antenna elements. By employing the two combined techniques of EBG and SNG, a reduction in the mutual coupling, represented by the transmission coefficient, between two closely-spaced patch antennas of about 20-30 dB is expected. It is worth mentioning that, the use of the EBG/SNG structures should not disturb the antennas far field or the consistency of the radiation patterns over the impedance bandwidth of the radiating system. The targeted frequency of operation is 28 GHz. This frequency band (i.e., 28 GHz) has recently received great interest because of the large amount of bandwidth of about 6 GHz, from 25 to 31 GHz, that is available for use. Moreover, this frequency band has been identified recently in Europe, USA, China and Korea for 5th generation (5G) wireless communication networks. The proposed radiating system is expected to possess a gain of 9-12 dB with a reasonable 3-dB gain bandwidth over the frequency band of 25 to 31 GHz. The antenna design will be fabricated at the Antennas and Microwave Structure Design Laboratory (AMSDL) Lab at KFUPM and will be tested and measured at KFUPM and at MVG-Italy company for the radiation patterns measurements. The estimated period of the project is not to exceed 18 months with a proposed budget of 99,866 SAR = USD 26,636.