[show abstract][hide abstract] ABSTRACT: A novel wideband built-in antenna with resonance frequency variability for digital video broadcasting-handheld (DVB-H) is proposed. The tunable antenna consists of two channel matching networks and a spiral-shaped monopole type radiator. Based on the matching networks combined with the switches, wide bandwidth and good radiation gains are obtained. As a demonstration, a wideband tunable antenna is designed and measured. The proposed antenna has an approximately omnidirectional radiation pattern and its peak gain is 3 dB greater than the required antenna gain covering DVB-H band. These features are suitable for DVB-H applications.
[show abstract][hide abstract] ABSTRACT: A patch antenna with dual-band and dual-polarization operation is proposed and discussed. For feeding the antenna, it is used the electromagnetically coupled microstrip-T junction and coplanar waveguide (CPW)-line. Since both ports of the antenna are electromagnetically coupled, the proposed antenna eliminates the need for capacitors in the RF path for active antenna applications. By using CPW resonant cell, the demonstrated approach results in a significant improvement in port isolation.
[show abstract][hide abstract] ABSTRACT: This paper describes new phase-shifterless beam steering techniques which exploit the synchronization properties of coupled nonlinear oscillator arrays. In each, the control parameters are the coupling phases of the local interactions between elements. The one-dimensional oscillator arrays under consideration are described by Phase Model- type equations, implying the assumption that the amplitude dynamics have achieved a steady state. Linear stability analyzes for each technique are provided which reveal significant differences in attainable scan angles.
[show abstract][hide abstract] ABSTRACT: A varactor-tuned active integrated antenna which is consisted of a series feedback voltage-controlled oscillator (VCO) and a matched slot antenna is proposed. The fabricated antenna has a stable oscillation at 5.8 GHz band, and the frequency varies form 5.73 GHz to 5.97 GHz, with less than 1.28 dB of amplitude deviation over the frequency range.
Antennas and Propagation Society International Symposium, 2005 IEEE; 08/2005 · 1.67 Impact Factor
[show abstract][hide abstract] ABSTRACT: This paper presents an active integrated antenna using a T-shaped microstrip-line-fed slot antenna which acts as DC isolation in the RF path and has a wide bandwidth. A fabricated parallel feedback antenna oscillator has a stable oscillation and a clean spectrum at the frequency of 10.05 GHz, which is only 0.5 % deviation from the designed frequency of 10 GHz. The measured EIRP is 37.79 mW, and the cross-polarization levels are at least -15 dB lower than the co-polarization ones for all directions.
Antennas and Propagation Society International Symposium, 2005 IEEE; 08/2005
[show abstract][hide abstract] ABSTRACT: In this letter, finite-difference time-domain analysis of the bow-tie antenna, including a feeding point, was studied by incorporating an approximated static field solution without additional computation time. By reformulating the static field solution in the rotated coordinate system, we can easily calculate the correction factors and obtain the result that shows a remarkable agreement with the method of moments result in spite of relatively coarse meshes.