The performance of the EVLA L-band feed/receiver across its full 1.0 – 2.0 GHz range is presented. The median efficiency across the band is near 45%, rising by about 4% near 1300 MHz and 2000 MHz, and dropping by a similar value near 1600 MHz. The efficiency drops quickly below 1100 MHz. The variation of focus position with frequency follows predicted values, and an optimum position for wide-ba...

Different slot structures have been widely used in numerous designs to produce antennas with enhanced bandwidths. In this paper, a printed slot antenna has been introduced as a candidate for use in the multi-band wireless communication applications. The antenna slot structure has a rectangular shape with its width, from the side of feed, has been modified in the form of Koch fractal curve of th...

a newly designed printed slot antenna is presented that incorporates variable two band-notched functions for ultra-wideband (uwb) applications. the two band notches of this coplanar waveguide (cpw) fed antenna are achieved by an m-shaped slot (mss) embedded in the radiating element and a c-shaped strip(css) close to ground plane, therefore two very narrow rejected properties in the wireless loc...

We determine the sensitivities of the EVLA and VLA antennas over their full tuning ranges through analysis of the correlation coefficients. Interim EVLA antennas can tune over the full range of 940 through 2200 MHz. The prototype L-band OMT shows good performance over its design frequency range. The betterperforming interim EVLA antennas meet the Project Book sensitivity requirements above ∼115...

Improved radio frequency interference suppression method based on short time Fourier transform applied to synthetic aperture radar is proposed in this paper. The radio frequency interference, including narrow-band interference and wide-band interference, are analyzed in time frequency domain. The interference is identified at instantaneous frequency spectrum by a novel threshold criterion in ti...

As part of an indoor mutt/path measurement system, discone antennas featuring simple N~onnector feed systems have bHn designed for the 1.0 to 2.0 GHz band. Extensive experimentation reveals that excellent performance (VSWR < 15:1 across the band) can be obtained with a simple "snap-on" feed/mount method, and that VSWR is most sensitive to the diameter of the disc feed conductor. Per· formance d...

Sandwiched frequency selective surface (FSS) is proposed as an additional reflection for a dual-frequency reflectarray system. The range of phase depends on the substrate thickness sensitively. Usually, tradeoff between smooth linear level and wide needed, especially By inserting FSS ground plane reflecting element layer, band provided. For higher band, layer plane. lower it transparent changed...

This paper introduces a class of high-speed wide-band frequency masking recursive digital filters with approximately linear-phase. These filters feature a high maximal sample frequency, low computational complexity, and good numerical properties.