نتایج جستجو برای: aperture antenna

تعداد نتایج: 71977  

1999
Tai-Lee CHEN

Microstrip leaky-wave antenna fed by an aperture-coupled microstrip operating at K-band is presented. Using the aperture-coupled microstrip as a feeding structure can fully exploit the wideband characteristic of the microstrip leakywave antenna. The dimensions of the antenna are obtained from the calculation of the propagation characteristics. Measurement shows a bandwidth of 22% for VSWR < 2 :...

2001
A. Boryssenko E. Boryssenko V. Ivashchuk V. Prokhorenko

The paper is devoted to design of impulse or equivalent ultra-wide band array antenna for subsurface radar system. Receiving elements of this antenna are arranged in array with small physical aperture and polarimetric features. Two transmitting element support two polarization states for radiating signals. The radar antenna provides down-looking scanning in subsurface medium for small areas cov...

2001
LARS M. H. ULANDER

Synthetic aperture radar (SAR) is a general method for generating high-resolution radar maps from low-resolution aperture data which is based on using the relative motion between the radar antenna and the imaged scene. Originally conceived in the early 1950s [1], it is extensively used to image objects on the surface of the Earth and the planets [2]. A synthetic aperture is formed using electro...

2015
Kay Y. Liu Elise C. Fear Mike E. Potter

For microwave imaging systems that utilize antennas with spatially separated feeds and apertures, arrival time correction based on the antenna aperture location is one of the fundamental steps in radar data processing. The estimates of the antenna aperture time and the corresponding average velocity in the material in contact with the antenna are expected to have a significant impact on the qua...

In this work, the method of iterative Fourier transform phase reconstruction, conventionally used in holography and optical image reconstruction, is applied to phase only synthesis of antenna patterns. The method is applied to two types of pattern synthesis problems: "main lobe beam shaping" and "side-lobe-level reduction". The proposed method is most useful in the efficient employment of attai...

2012
Manoj Kumar Dubey Rahul Vivek Purohit

In this paper dual band aperture coupled Circularly Polarized (CP) C-Slotted antenna with a small frequency ratio exited through a single feed is proposed for GPS application. The optimized design of CSlot antenna has been validated using IE3D Electromagnetic wave simulator. The C-slot is asymmetrical about the centre of the antenna. The antenna parameters can be optimized by changing the physi...

A. Heidary and M. Kyvanfar, M. Kahrizi,

Analysis of aperture-coupled microstrip antennas with a superstrate using space domain closed form Greens functions is presented. Integral equations are derived from applying the boundary conditions on the radiating patch, across the aperture, and on the microstrip feedline. The computation of space domain greens functions is performed using the closed-form. The solution of the integral equatio...

2009
Karthik Srinivasan Ashutosh S. Limaye Charles A. Laymon Paul J. Meyer

Electronic beam steering capability of phased array antenna systems offer significant advantages when used in real aperture imaging radiometers. The sensitivity of such systems is limited by the ability to accurately calibrate variations in the antenna circuit characteristics. Passive antenna systems, which require mechanical rotation to scan the beam, have stable characteristics and the noise ...

2009

Microstrip patch antennas are well suited for integration in to many applications owing to their conformal nature. There are many wide banding techniques used for the MSAs. But many wide banding techniques such as using slots in the patch require an inductive coupled feed (probe feed). But complete planar (2D) processes for manufacturability needs capacitive coupling. Capacitive coupling with c...

1999
Takafumi FUJIMOTO Kazumasa TANAKA Mitsuo TAGUCHI

The formulation of the wall admittance of a circular microstrip antenna by the spectral domain method is presented. The circular microstrip antenna is calculated using the cavity model. The electromagnetic fields within the antenna cavity are determined from the impedance boundary condition at the side aperture. The contribution from the region outside the antenna is taken into account by the w...

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