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Multiband rectangular-shaped ring antenna embedded with inverted S- and C-shaped strips for WLAN/WiMAX/UWB applications
This research work presents a microstrip-fed antenna that is small, low-profile, planar, and suitable for WLAN/WiMAX and partially ultra-wideband (UWB) applications. The radiating element of the proposed antenna consists of rectangular-shaped ring embedded with a three inverted ?S?-shaped and inverted ?C?-shaped strips. This antenna is capable of generating penta bands having good impedance matchi
Design and implementation of Butler matrix-based beam-forming networks for low sidelobe level electronically scanned arrays
In this work, the design, fabrication, and testing of low sidelobe level (SLL) Butler matrix-based beamformers is presented. The paper is divided in two parts. The first part deals with the conventional technique of simultaneous excitation of input ports. The second part introduces some novel modified low SLL Butler matrices, as an alternative advantageous design choice. Circuit architecture makes
Two novel memory polynomial models for modeling of RF power amplifiers
Two novel memory polynomial models are derived based on physical knowledge of a general power amplifier (PA). The derivations are given in detail to facilitate derivations of other model structures. The model error in terms of normalized mean square error (NMSE) and adjacent channel error power ratio (ACEPR) of the novel model structures are compared to that of established models based on the numb
A programmable compact wide-band RF feed network
The design and fabrication of a wide-band programmable radio frequency (RF) feed network is proposed. It is designed to cover a wide band from 2.5 to 6 GHz over two separate branches. The feed network is simulated and fabricated on an FR-4 substrate with 0.8 mm thickness. Good matching between simulation and measurement results is achieved. The measured amplitude resolution was 0.5 dB with a maxim
Transient response of dual-band-notched ultra-wideband antenna
In the present study, an ultra-wideband (UWB) antenna has been proposed using coplanar waveguide (CPW) feed with dual-band-notch characteristics. Slot-loaded radiator and U-shaped CPW resonator are used for band rejection at 3.5 and 5?6 GHz respectively to reduce interference with existing World interoperability for microwave access and wireless local area network systems. With an extended operati
Design and analysis of stair-shape UWB antenna with flowery DGS
In this paper, staircase-shaped ultra-wideband (UWB) response is proposed. UWB technology being emerging technology of decade needs development of antennas with small size. This paper proposed the design of antennas for UWB technology with small overall size. The feed used in the proposed design is microstrip feed line. The defected ground structure and staircase patch have been used to enhance ba
TDOA estimation method using 60 GHz OFDM spectrum
In the field of high data rate wireless communications, localization issues play a key role in achieving energy-efficient communication and geographic routing. time-difference of arrival (TDOA)-based localization methods present numerous advantages. In this paper, a new method of TDOA estimation is proposed. With this method, unlike conventional TDOA measurements, it is possible to perform communi
Beam-steering in a three-element circular antenna-array
A simple and volume efficient circular antenna-array design with a low profile programmable beam rotation mechanism was presented. The proper selections of the rotation vector and the excitation coefficients of rectangular array-elements were made for rotation of the beam. The proposed rotation mechanism was capable to rotate the radiation pattern at any desired speed and to transmit in any desire
Evaluation of coaxial cable performance under thermal gradients
This paper presents a very flexible tool for numerically evaluating the small-signal and noise parameters of a transmission line subject to an arbitrary thermal gradient. Contrary to previous methods, the proposed approach allows straightforwardly taking into account possible variations of electrical parameters along the propagation direction, such as may be expected when temperature ranges betwee