Feed line

About: Feed line is a research topic. Over the lifetime, 5231 publications have been published within this topic receiving 53539 citations.

Single, Dual and Tri-Band-Notched Ultrawideband (UWB) Antennas Using Capacitively Loaded Loop (CLL) Resonators

Abstract: Two compact, printed, ultrawideband (UWB) monopole antennas with tri-band notched characteristics are reported. The notched filters are achieved by introducing printed, electrically small, capacitively-loaded loop (CLL) resonators. The directly driven elements consist of printed top-loaded CLL-based monopoles and 50 Ω microstrip feed lines. By adding three CLL elements close to the feed line, band-notch properties in the WiMAX (3.3-3.6GHz), lower WLAN (5.15-5.35GHz) and higher WLAN (5.725-5.825GHz) bands are achieved. Each antenna system is contained on a 27×34mm2 sheet of Rogers Duroid 5880 substrate. One is designed with three additional CLL elements; the other is achieved with only two. Comparisons between the simulation and measurement results show that these UWB antennas have broadband matched impedance values and stable radiation patterns for all radiating frequencies.

Analysis of a wide radiating slot in the ground plane of a microstrip line

Abstract: An analysis of a wide rectangular radiating slot excited by a microstrip line is described Coupled integral equations are formulated to find the electric current distribution on the feed line and the electric field in the aperture The solution is based on the method of moments and using the space domain Sommerfeld-type Green's function The information about the input impedance or reflection coefficient is extracted from the electric current distribution on the microstrip line utilizing the matrix pencil technique The theoretical analysis is described and data are presented and compared with other theoretical and experimental results >

A Compact Tri-Band Monopole Antenna With Single-Cell Metamaterial Loading

Abstract: A compact tri-band planar monopole antenna is proposed that employs reactive loading and a ?defected? ground-plane structure. The reactive loading of the monopole is inspired by transmission-line based metamaterials (TL-MTM), which enables the loaded antenna to operate in two modes. The first resonance exhibits a dipolar mode over the lower WiFi band of 2.40 GHz - 2.48 GHz, and the second resonance has a monopolar mode over the 5.15-5.80 GHz upper WiFi band. Full-wave analysis shows that the currents of the two modes are orthogonal to each other, resulting in orthogonal radiation patterns in the far field. The feature of a ?defected? ground-plane, formed by appropriately cutting an L-shaped slot out of one of the CPW ground-planes, leads to the third resonance that covers the WiMAX band at 3.30-3.80 GHz. Air bridges at the intersection between the antenna and the CPW feedline ensure a balanced current. A fabricated prototype has compact dimensions of 20.0 mm × 23.5 mm × 1.59 mm, and exhibits good agreement between the measured and simulated S parameters and radiation patterns. The measured radiation efficiencies are 67.4% at 2.45 GHz, 86.3% at 3.50 GHz and 85.3% at 5.50 GHz.

Phased array antenna system including a coplanar waveguide feed arrangement

Abstract: The disclosure relates to a phased array antenna for microwave and millimeter wave applications, using either microstrip line, coplanar waveguide, or other construction techniques incorporating a solid dielectric transmission line. A continuously variable phase delay structure which is used to control the beam pattern of the phased array antenna can be applied to the construction of resonant frequency tunable coplanar waveguide antennas and impedance tunable quarter-wave transformers. A thin film of barium strontium titanate (Bax Sr1-x TiO3) or other nonlinear material such as PbZrx Ti1-x O3 (PZT), LiNbO3, etc. is deposited upon the coplanar waveguide, and/or the patch antenna element. The dielectric constant of the thin film can be made to vary significantly by applying a DC voltage to the thin film. The propagation constant of a transmission line is directly proportional to the square root of the effective dielectric constant (assuming a lossless dielectric). In an array of multiple antenna elements provided with the feed structure using the disclosed transmission lines, the direction of the resultant main beam of the array can be made to vary over a complete half-sphere with only two adjustable DC voltages applied to the dielectric thin films.

Microwave ablation instrument with a directional radiation pattern

Abstract: A medical instrument is disclosed The medical instrument includes a transmission line suitable for the transmission of electromagnetic energy and an antenna coupled to the transmission line The antenna is configured for generating an electromagnetic field sufficiently strong to cause tissue ablation The medical instrument further includes a reflector arranged to be electrically coupled to the transmission line The reflector is positioned laterally to a first side of the antenna and configured for redirecting a portion of the electromagnetic field to a second side of the antenna opposite the reflector, wherein a majority of the electromagnetic field is directed away from the second side of the antenna