International Journal

In this paper, the designs and experimental performances of wideband (higher than one octave) high-efficiency, high-power amplifiers (HPA) working in the 1?4 GHz range, using the same GaN process, are presented. They are based on the Bode?Fano integrals, which can be applied to a trade-off calculation between bandwidth and efficiency. Firstly, an microwave intregrated circuits (MIC) wideband HPA,

This paper presents results of direction of arrival (DOA) estimation using multiple signal classification (MUSIC), Root-MUSIC, and estimation of signal parameters via rotational invariance technique algorithms. As is well known, these algorithms are mainly based on the specific properties of the signal covariance matrix as well as the decomposition of the observation space into two subspaces, one

This paper presents the analysis and design of a wideband asymmetrical Doherty amplifier. The frequency response of the output combining network of the Doherty amplifier with arbitrary back-off level configuration is analyzed. Other bandwidth-limiting factors were discussed and analyzed as well. A number of performance enhancement techniques were taken into consideration to obtain high and flat ba

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

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 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

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

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

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

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