Parametric Study And Design Of Microwave And Millimeter Wave Antennas/Arrays For IoT Based Indoor/Outdoor Applications

Antenna is a very important element and plays a key role in communication systems for radiating energy.Based on high data rate speed requirements and large volume multimedia applications,3G,4G and now 5G technologies have been introduced and implemented.In the recent technological development of 5G communication systems either cellular or other wireless applications,a lot of research is being done on millimeter-wave antenna arrays.High frequency antennas in millimeter-wave range are used to achieve high speed communications with the data rate in Gb/s.Millimeter-wave technology has opened a new era of wireless communication systems in various fields like automotive,mobile devices,Io T(internet of things),military,medical and others.The benefit of adopting the unconventional frequency spectrum of large bandwidth under a millimeter-wave(mm-Wave)spectrum is an availability of large bandwidth and lesser chances of interferences from various technologies.In the recent 5G communication systems either cellular or other wireless applications,many researchers has focused on millimeter-wave antennas and arrays.Internet of things(Io T)is expected to be adopted for most of the electronic communication applications in near future with 5G technology.The polarization diversities and frequencies will work at several bands in future.Io T is bringing an advanced digital revolution to our daily life.As a result,there is a huge production of sensors and integrated antennas associated with Io T age.The Io T technology associated with integrated antennas is expected to make our future communications a very sophisticated and simple.The concept of internet of things(Io T)is known as the extension of internet now.It is a worldwide interconnected emerging network of different objects associated with sensors,input/output devices,actuators and communication systems.The efficiency of internet of things(Io T)and wireless internet connection are improved with the wireless sensor technology.In fact,antennas are playing a vital role in wireless sensor technology that leads to an emerging future with the development of Io T techniques.The compact and low profile integrated antennas have drawn a large attention in last few years due to multi-band and multi-function features in communication systems.In this thesis,authors are going to design different broadband 5G antennas and arrays in microwave and millimeter wave ranges to demonstrate the features of broadband,multiband and high data rate for indoor/outdoor 5G-Io T and base station applications.Furthermore,an antennaradome system for all types microwave /mm-Wave anennas is designed for secure communications.For demonstration of this system,a horn antenna is designed and excited in the microwave range9.4-16 GHz under the proposed antenna-radom that has two separate frequency selective screens to give the bandstop and bandpass features with radom.This feature makes antenna communication untraceble and secure.The main contents of this theis are summarized as follows:1.The 5G antenna/ array in microwave region covers three different bands from 5G NR frequency spectrum at the same time i.e.3.6-3.85 GHz,4.05-4.20 GHz,and 4.8-5.15 GHz with 15 d B return loss.This gives 8.12 d Bi gain with 70.7° half-power beamwidth(HPBW)for single element antenna and 16.65 d Bi gain with 69° HPBW for 1×8 antenna array.The triple-band dualpolarized feature with very high isolation,cross-polarization discrimination ratio(XPD)and front to back ratio(FBR)makes this profile antenna array a suitable candidate for 5G-Io T and base station applications.2.A low profile novel structure antenna gives a large continuous bandwidth at 28 GHz center frequency for broadband and millimeter-wave 5G-Io T applications.It is an H-plane printed horn antenna with multi-layered sandwich substrate that gives an impedance bandwidth 20-45 GHz with S11 <-10 d B and 8.64 d Bi gain.3.A broadband single substrate dual-antenna array is designed at 38 GHz with a compact series feed network for smartphones and other 5G-Io T applications.It has two 1×16 arrays on a single substrate in the broadside direction at opposite edges.Each array exhibits 17.3 d Bi and 16.4d Bi simulated and measured gain with 65.7° HPBW at 38 GHz and impedance bandwidth 31.30 GHz to 39 GHz.4.An efficient X-band antenna-radome system is designed for airborne and ground applications.The Radome with dielectric sandwich wall configuraton and FSS screens gives bandpass and bandstop feature without affecting antenna gain over the frequency range 9.4-16 GHz.The bandpass and bandstop features make this proposed FSS-antenna-radome a good candidate for ground and airborne applications for secure and untraceable communications.In bandpass feature,antenna becomes inaccessible to other antennas/radars except a narrow band.5.For underwater applications,performance of a Submarine Radome is analyzed with various wall configurations and two different shapes and AT-6000 antenna specifications.A novel shape Radome structure is proposed for submarines that faces less stress and deformation with the increasing depth under water as compared to a typical barrel shape structure and can operate in high collapse depths under sea water.Ansys 18.2 HFSS is used for optimization and simulation of the antennas and arrays.Additionally Siemens NX software is used for submarine Radome design and its hydro pressure test.