A planar antenna with pentagon shaped tuning stub and asymmetric rectangular ground plane width along with wide rectangular aperture is presented for triple band operation. A novel concept of use of feed coupling slot as inherent band-notch at 4 GHz and design of wide rectangular aperture with length and width at λ/4 and λ of WLAN 802.11b and 802.11a resonating frequency respectively with varia...

This paper describes the design of a compact, dual GPS frequency L1/L2, multi element adaptive antenna array, where each array element is comprised of an aperture coupled spiral slot array. In short, it is an array of arrays. The design of a seven element array is described. The design is quite different from existing CRPA antennas which use a stacked patch approach. The aperture coupled spiral...

Due to the fact that the imaging distance is similar to the dimension of synthetic aperture antenna in near-field, the Fourier imaging theory used in the traditional synthetic aperture imaging radiometer (SAIR), which is based on the far-field approximation, is invalid for near-field synthetic aperture imaging. This paper is devoted to establishing an accurate imaging algorithm for nearfield mi...

We propose a scheme to measure and correct anomalous refraction effects for millimeter wave antennas. A radiometer tuned to the 183 GHz atmospheric water vapor line scans the atmosphere above the aperture of an antenna to determine the spatial derivative of the refractive index. In an array of antennas, such as the MMA, it would be used simultaneously to measure the phase delay correction for t...

Distributed aperture radars represent an interesting solution for target detection in strong interference environments. Distributed apertures provide improved angular resolution or are able to view a target from multiple look-angles, thereby exploiting scintillation. However, due to the large distances between array elements, both target and interfering sources are in the near field of the ante...

In this paper describe the different feeding technique for wireless microstrip antenna, which are microstrip line feed, coaxial plane feed, proximity coupled feed and aperture couple feed. Microstrip line and coaxial probe feeds are contacting scheme, in which RF power directly to the radiating patch. Proximity and Aperture coupled feeds are non contacting schemes ,in which electromagnetic fiel...

A new promising architecture of microwave personnel screening system is analyzed in this paper with numerical simulations. This architecture is based on the concept of inverse aperture synthesis applied to a naturally moving person. The extent of the synthetic aperture is formed by a stationary vertical linear antenna array and by a length of subject’s trajectory as he moves in the vicinity of ...

The start-stop approximation is a standard tool for processing radar data in synthetic aperture imaging. It assumes that the antenna is motionless when a pulse is emitted and the scattered signal received, after which the antenna moves to its next sending/receiving position along the flight track. However, when the antenna is mounted on a satellite, as opposed to an airplane, its relatively hig...

High-gain and large-aperture antennas with fixed beams are required to achieve high S/N ratio for point-to-point high-speed data-communication systems in the millimeter-wave band. Furthermore, beam-scanning antennas are attractive to cover wide angle with high gain for applications of high-speed data-communication systems and high-resolution sensing systems. High-gain pencil-beam antennas are u...

The characteristics of dielectric backed planar conducting layers of arbitrarily shaped in a rectangular waveguide are calculated by means of coupled integral equation technique (CIET) which accurately takes higher order mode interactions. Equivalent structures for the accurate analysis whole structure are introduced in which magnetic surface currents are identified as the unknowns at the apert...