Phased array antennas, capable of controlling the direction of their radiated beam, are demanded by many conventional as well as modern systems. Applications such as automotive collision avoidance radar, inter-satellite communication links and future man-portable satellite communication on move services require reconfigurable beam systems with stress on mobility and cost effectiveness. Microwave phase shifters are key components of phased antenna arrays. A phase shifter is a device that controls the phase of the signal passing through it. Among the technologies used to realize this device, traditional ferrite waveguide phase shifters offer the best performance. However, they are bulky and difficult to integrate with other system components. Recently, ferrite material has been introduced in Low Temperature Co-fired Ceramic (LTCC) multilayer packaging technology. This enables the integration of ferrite based components with other microwave circuitry in a compact, light-weight and mass producible package. Additionally, the recent concept of Substrate Integrated Waveguide (SIW) allowed realization of synthesized rectangular waveguide-like structures in planar and multilayer substrates. These SIW structures have been shown to maintain the merits of conventional rectangular waveguides such as low loss and high power handling capabilities while being planar and easily integrable with other components. Implementing SIW structures inside a multilayer ferrite LTCC package enables monolithic integration of phase shifters and phased arrays representing a true System on Package (SoP) solution. It is the objective of this thesis to pursue realizing efficient integrated phase shifters and phased arrays combining the above mentioned technologies, namely Ferrite LTCC and SIW. In this work, a novel SIW phase shifter in ferrite LTCC package is designed, fabricated and tested. The device is able to operate reciprocally as well as non-reciprocally. Demonstrating a measured maximum reciprocal phase shift of 132o and maximum non-reciprocal shift of 118o at 12 GHz. Additionally a slotted SIW antenna is designed and integrated with the phase shifter in an array format, demonstrating a beam scanning of ± 15o. The design is highly suitable for mobile automotive radars and satellite communications systems.

The current and future demand for wireless technology is increasing rapidlyin the era of Internet-of-things, information-shower, auto-drive vehicles andthe fifth generation of mobile communications. The flourishing in wirelesstechnologies comes from their advantages such as mobility, flexibility, easy toextend, easy to install and easy to do the maintenance. However, the wirelesstechnology is suffering from many problems such as; lack of security andthe shortage of spectrum bands. The security remains a major challenge forthe wireless communications because of the broadcasting nature of wirelesssignals and massive researches have been conducted to deal with it. Beamformingis one of the physical layer security solutions that is proposed toimprove the security by focusing the majority of the transmitted power towardthe legitimate destination. The main concern about the beamformingtechnique is the relatively small amount of power that escapes from the sidelobes where any illegal user equipped with a sufficiently sensitive receivercan detect its information. The literature has been received many differentsolutions to secure the side lobes emissions. These solutions suffer from fourcommon limitations; 1) the need to modulate the signal at the antenna level,2) the data rates are restricted by the switching speed, 3) they can not easily beintegrated with the current infrastructure, and 4) they work only with phasemodulation. In this thesis, a new, simple, economic, easy to get integratedwith current phased array systems and effective solution has been proposedand analytically analysed under different circumstances, including noiseless,noisy and Rician fading channels and the effect of phase shift errors. The secondproblem addressed in this thesis is the poor spectral efficiency of spaceshift keying modulation. This thesis proposes a new physical layer directcode to improve the spectral efficiency of space shift keying modulation byexploiting the indices of both active and inactive transmitting antennas.

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