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Basic of 5G Networks: Review
Published in Ashish Bagwari, Geetam Singh Tomar, Jyotshana Bagwari, Advanced Wireless Sensing Techniques for 5G Networks, 2018
A.N. Ibrahim, M.F.L. Abdullah, M.S.M. Gismalla
Currently, all of the electronic devices use the specific radio frequency spectrum which is commonly limited up to 30 GHz. This entire range of the radio frequency is currently highly congested because of the rapid increase in the number of mobile users. Hence, the future mobile communication standards are focusing more on standards in order to use more than 30 GHz of the radio frequency band. The mmWave spectrum recently attracted research interest among researchers and technologists since the extremely large available bandwidth could potentially lead to rates of multiple Gbps per users [20]. The broadcasting frequency of the mmWave spectrum is 30–300 GHz as compared to the currently broadcasting frequency used for mobile devices which is 6 GHz [20]. Additionally, there are several bands which have been considered, such as multipoint distribution service band (28–30 GHz), E-band (71–76 GHz, 81–86 GHz, and 92–95 GHz), and the license free band (60 GHz) [10]. If all of these bands were implemented, several tens of GHz would become available for the future 5G technology, which is also offering more bandwidth compared to the current systems [10].
Compact Microstrip Diplexer Based on CRLH Metamaterial Concept
Published in IETE Journal of Research, 2020
There is a growing demand for realizing and implementing diplexers especially in multiservice and multiband communication systems [1]. A diplexer is a three-port device with one input port and two output ports, which is an essential component in mobile communication systems because such device can be used with the transceiver antenna/array to transmit and receive the signals simultaneously at separate frequency bands using single feeder circuit. According to the center frequency of each channel, the diplexers can separate the signals from the same input port to transmit/receive channels which are connected to a common antenna. The traditional approach to design a microstrip diplexer is to combine two different bandpass filters operating at different frequencies. Several diplexers have been proposed on microstrip, substrate integrated waveguide (SIW), and cavity technologies with different techniques such as open-loop ring resonators [2], dual-mode stub-loaded resonators [3,4], half- and quarter-wavelength resonators [5], short stub-loaded composite right/left handed resonator [6], CRLH (composite right/left-handed) and RH (right-handed) isolation circuits [7], coupled lines [8], E-band cavity [9], dual-mode cavities [10], evanescent-mode technique [11], and slot line-loaded microstrip ring resonator [12]. High cost and large size have limited the application of the traditional microstrip and SIW diplexers. It is observed that, in most of the proposed diplexers, the circuit size is relatively large. Accordingly, there is an essential requirement in terms of size reduction to achieve high-performance diplexers with small size.