This paper is a review of amateur-built high-directivity wire antennas, for wireless local area network (WLAN), operating at 2.4-GHz frequency range. Those antennas can be deployed for range extension and interference reduction, for example. Covered in this review are a biquad antenna with reflector, Yagi-Uda antenna, and helical antenna. The distinctive feature of these antennas is their ease ...

Selection of the most suitable substrate for a Microstrip antenna is a matter of prime importance. This is because many limitations of the microstrip antenna such as high return loss, low gain and low efficiency can be overcome by selecting an appropriate substrate for fabrication of the antenna, without shifting the resonant frequency significantly. The substate properties such as its dielectr...

A dual-polarized Ka-band feed based on gap waveguide (GW) technology for an ultra-high-gain reflector antenna is presented. The provides SUM-beams data transfer and DIFF-beams tracking. whole composed of the a dual-reflector Cassegraine antenna. has been prototyped, measured reflection coefficients horizontally vertically polarized SUM-beam ports are below -10 dB -8 over 30.8-38 GHz, respective...

A transient quasi-analytic method is improved to analyze the offset reflector for impulse radiating antenna (IRA) applications. Physical optic (PO) approximation and analytic time transform (ATT) are utilized to investigate the time domain (TD) radiating characteristics of the offset reflector. With the appropriate coordinate transformation, the TD far-field integral problem can be simplified t...

In this research paper, a slotted coaxial line fed cross dipole excitation structure for short backfire antenna is proposed and developed to achieve reconfigurable circular polarization. The cross dipole, which is fed by the slotted coaxial line, consists of two orthogonal dipoles. The dipoles are mounted on the outer conductor of the coaxial line. A unique technique is developed to generate re...

A two-dimensional (2D) diffraction model for the calculation of the diffraction field in 2D space and its applications to terahertz parallel-plate waveguide power splitters are proposed in this paper. Compared with the Huygens-Fresnel principle in three-dimensional (3D) space, the proposed model provides an approximate analytical expression to calculate the diffraction field in 2D space. The di...

In this note we begin the development of two types of Impulse Radiating Antenna (IRA). o These two designs include a 23 cm diameter reflector IR4, with an F/D of0.38, and a solid dielectric-lens IIU4, or dielectric-immersed lens IIU. This latter design is a Transverse Electromagnetic (TEM) horn immersed in a dielectric, with a prolate spheroidal lens interface to air. The reflector IR4 consists...

A novel method of enhancing radiation performance is demonstrated by applying a hybrid reflector composed inhomogeneous metamaterial elements to four-arm log-periodic toothed antenna. The operation the antennas various cells observed, and causes deterioration narrow bandwidth are investigated through field distribution analysis. arranged in suitable positions under antenna for good wide accordi...

Measurements of the antenna patterns for the high frequency component of the Advanced Microwave Sounding Unit (AMSU-B), to fly on the NOAA-KLM polar orbiting satellites, are reported here. They were made on the Compact Antenna Test Range at Queen Mary and Westfield College, London, at three frequencies within the AMSU-B receiver's channels, centered at 89, 150, and 183.31 GHz. The main reflecto...

Different satellite systems have been defined to provide broadband communications and internet access in remote geographical areas in Ka band (20-30 GHz) [1-2], being the up-link at 30 GHz and the down-link at 20 GHz. Costeffective antennas are required for fixed and portable terminals in Ka-band. Conventional reflectors are a preferred option to maintain reduced costs. However, the different r...