Search

A new compact ultra-wideband (UWB) filtering antenna having good band-edge selectivity and suppressed unwanted harmonics is proposed in this paper. The proposed UWB filtering antenna is obtained by integrating modified elliptic-shaped UWB antenna with super-compact UWB bandpass filter (BPF). Initially, a UWB antenna is designed and investigated through numerical simulation and experimentally. Further, the geometrical parameters of BPF are optimized using numerical simulation software for its integration with the proposed UWB antenna to improve the passband selectivity and unwanted harmonic suppression capability of the proposed UWB filtering antenna. The proposed UWB filtering antenna has simulated −10 dB impedance bandwidth of 7.65 GHz (3.07-10.72 GHz) and unwanted harmonic suppression up to 30 GHz. It has nearly stable omnidirectional radiation patterns over whole UWB frequency band. The proposed filtering antenna was fabricated and experimentally tested. The experimental results for the filtering antenna are nearly in agreement with corresponding simulation results. [ABSTRACT FROM AUTHOR]

A super-compact ultra-wideband (UWB) microstrip band-pass filter (BPF) with good selectivity and wide stopband is proposed in this paper. The super-compactness along with wide stopband of the proposed filter is achieved by integrating modified multimode resonator-based UWB BPF and defected ground structure (DGS)-based compact low-pass filter (LPF). The LPF structure is designed using four non-uniform configurations of DGS units along with a 50 Ω microstrip line. Each DGS unit is formed by cascading three isosceles U-shaped DGSs. Further, an equivalent RLC circuit model of the LPF is proposed to validate the numerical simulation and experimental results of LPF. The proposed filter has simulated passband frequency range 3-11 GHz with wide stopband: attenuation better than 40 dB and 25 dB over the frequency ranges 11.7-20.5 GHz and 11.2-30 GHz respectively. The experimental results for the proposed filter are nearly in agreement with corresponding numerical simulation results. [ABSTRACT FROM AUTHOR]

The theoretical and experimental investigations carried out on a gap-coupled microstrip array antenna reveal that there is a significant improvement in VSWR and bandwidth characteristics of the gap-coupled microstrip array antenna as compared with a conventional microstrip array antenna. The input impedance and the resonant frequency of the gap-coupled patch are found to depend heavily on the gap length as well as on the dielectric constant of the substrate material. [ABSTRACT FROM AUTHOR]

A new ferrite fed microstrip scanning array antenna is proposed which is capable of beam scanning in the azimuthal plane as well as in the elevation plane. The antenna consists of eight microstrip arrays, each having six elements in cascade. The antenna is fed with a ferrite loaded rectangular to circular waveguide transition. The coupling between the feed system and different arrays is achieved through slots cut in the circular waveguide. Theoretical investigations of the proposed antenna exhibit a beam scanning of ±180° in the azimuthal plane with the help of dc bias and 90° in the elevation plane for ±750MHz deviation. A scan rate of 0.06° MHz 1 is achieved for each array antenna in the elevation plane, which makes it suitable for radar. Continuous uniform beam shift is observed during scanning. [ABSTRACT FROM AUTHOR]