In a mobile and wireless system, a base station (BS) transmits and receives signals from a multitude of cellular phones or mobile terminal (MT) units. Generally in the past, the simplest BS architecture is the omni-directional BS, which transmits and receives RF signals in all directions. So, it is a waste of resources and generates too much interference between information systems. Nowadays, we can increase BS capacity by using directional antennas to partition the cell into multiple sectors. The directional antennas or a similar antenna can be known as smart antenna. Switched beam and adaptive array systems are one of smart antenna category, which enable a base station to customize the beams they generate for each remote user effectively by means of internal feedback control. Smart antennas (also known as adaptive array antennas, multiple antennas and recently MIMO) are antenna arrays with smart signal processing algorithms used to identify spatial signal signature such as the direction of arrival (DOA) of the signal, and use it to calculate beam forming vectors, to track and locate the antenna beam on the mobile/target. The antenna could optionally be controlled the beam in several schemes to direct to the desire of arrival signal to maximize performance metric (e.g., SNR, signal energy and channel capacity).
This dissertation deals with the development of new trend smart antennas for next-generation wireless communications base stations. Reconfigurable and switched four port antenna arrays for smart antenna applications have been designed and inspected. The integration of antenna elements, feed and bias switching network is considered, build with optimal and compact size that appropriate for array configuration in order to have a reconfigurable beam pattern. Novel cubic antenna array configuration has been reported in this work also. The cubic array is composed of four reformed modified monopoles which are orthogonal to each other. Good agreement between simulation and measurement can be seen moreover, channel capacity for MIMO system also investigated to demonstrate the antenna design. In additional, a multiframe L-slot planar printed dipole loaded with a single strip-line has been investigated for multiband antenna systems. The designed prototype is appropriate for indoor wireless system and covers various communication standards (LTE, WLAN, WiMax and WiBro etc.). Finally, multiband dual polarization, dual antennas for beam switched antenna system suitable for small cell base stations has been presented and tested in this thesis. The whole design consists of horizontal and vertical antennas on a single PCB. This novel design covering LTE and WLAN wireless standards has been thoroughly investigated through numerical simulations using commercially available EM analysis software. And then the fabricated antenna samples is demonstrated the performances by a number of measurements (S-parameters, beam patterns and MIMO performances).
모바일 및 무선 시스템에서,기지국 (BS )을 송신하고, 휴대 전화 나 휴대 단말기 ( MT ) 단위 의 다수 의 신호를 수신한다. 일반적으로과거에 ,BS 간단한 아키텍처는 송신하고, 모든 방향으로 RF 신호를 수신하는전 방향성 BS 이다. 그래서, 자원의낭비 및 정보 시스템 사이에서 너무 많은 간섭을 생성한다. 요즘 , 우리는 여러 분야로 셀을 분할하기 위해 지향성 안테나 를 사용하여 BS 용량을 증가시킬 수있다. 지향성 안테나 또는 유사한 안테나는 스마트 안테나 라고 할 수있다. 스위치 빔과 적응 어레이 시스템 은 내부 피드백 제어 에 의해 효과적으로 각 원격 사용자에 대해 생성하는 빔 을 사용자 정의 할 기지국 을 사용 스마트 안테나 의 종류 중 하나 입니다. ( 또한, 어댑티브 어레이 안테나 , 다수의 안테나 및 최근 MIMO 로 알려진 )
