Wafer-scale defect-free planar III-V nanowire (NW) arrays with ∼100% yield and precisely defined positions are realized via a patterned vapor-liquid-solid (VLS) growth method. Long and uniform planar GaAs NWs were assembled in perfectly parallel arrays to form double-channel T-gated NW array-based high electron mobility transistors (HEMTs) with DC and RF performance surpassing those for all fie...

Planar waveguide slot arrays (WSAs) have been used since 1940 and are currently as performing antennas for high frequencies, especially in applications such communication RADAR systems. We present this work a review of the most typical array configurations proposed literature, describing their main limitations drawbacks along with possible effective countermeasures. Our attention has focused ma...

We consider the use of an arbitrary planar array for direction-ofarrival (DOA) estimation, with the commonly used Cramér-Rao Bound (CRB) as a performance measure. By taking advantage of the cosine structure of the array Fisher information matrix (FIM), the FIM is reformulated to be completely represented by three parameters which depend on the array geometry, leading to a new FIM expression tha...

An innovative method for antenna arrays beam configuration is presented. In the proposed method, every element of the array is connected to its feed through a switch, so that it can be active or passive, depending on the switch position. Pattern reconfigurability is achieved by appropriately switching on or off the array elements. The optimal configuration of the switches for each of the radiat...

Broadcasting, radar, sonar and space telecommunication systems use phased arrays to produce directed signals be transmitted at the desired angle. This system requires a large number of antenna elements. The presence faulty element(s) in an array causes asymmetry, which results deformed radiation pattern with higher sidelobe levels. Higher levels indicate waste energy by transmitting receiving u...

■ The challenge of precision source location with a radio-frequency antenna array has existed from the beginnings of radiometry and has continued in modern applications with planar antenna arrays. Early work in this field was limited to estimating single source directions in one dimension with systems like crossed-loop radiometers. Currently, more advanced systems attempt to estimate azimuth an...