Shi-Wei Qu

A Band-Notched Ultrawideband Printed Monopole Antenna

In this letter, a band-notched ultrawideband (UWB) antenna is presented and the notched-band characteristic is realized by a compact coplanar waveguide (CPW) resonant cell (CCRC). The antenna with a total size of 46 mm

Bandwidth Enhancement of Wide-Slot Antenna Fed by CPW and Microstrip Line

,times,

Wideband and High-Gain Composite Cavity-Backed Crossed Triangular Bowtie Dipoles for Circularly Polarized Radiation

30 mm operates in a band from 2.67 to over 12 GHz, and shows omnidirectional radiation patterns. Measurements indicate that the antenna presents a notched band from 5.10 to 5.94 GHz for

Wideband Cavity-Backed Bowtie Antenna With Pattern Improvement

VSWR ge 3:1

EFFECT OF ROUND CORNERS ON BOWTIE ANTENNAS

, which covers the wireless local area network (WLAN) band. The time-domain behaviors and the CCRC are discussed and the group delay is given experimentally. Also, parametric studies are performed numerically in the end.

Wideband and Unidirectional Cavity-Backed Folded Triangular Bowtie Antenna

Two printed wide-slot antennas with square patches within an arc-shape slot are proposed in this letter. They are fed by a coplanar waveguide (CPW) and a microstrip line with almost the same performances. Their impedance bandwidths for

Ultrawideband Composite Cavity-Backed Folded Sectorial Bowtie Antenna With Stable Pattern and High Gain

S_11leq -10~ dB

Ultrawideband Strip-Loaded Circular Slot Antenna With Improved Radiation Patterns

are enhanced largely to more than 158%. The radiation patterns are given at 2, 6, and 10 GHz.

Single-Layer Dual-Band Reflectarray With Single Linear Polarization

A composite cavity-backed antenna excited by crossed triangular bowtie dipoles is proposed and investigated for circular polarization (CP) applications. It is fed by a novel balun, i.e., a transition from a microstrip line to double slot lines, providing symmetrical electric field distributions at the feeding port. Measurements of an optimized antenna prototype show that it can achieve an impedance bandwidth of over 57.6% for SWR ≤ 2, a 3-dB axial-ratio bandwidth of 39%, a broadside gain of 8-10.7 dBi, and symmetrical radiation patterns over the whole operating band. The operating principles of the proposed antenna are analyzed carefully and found quite different from crossed thin-wire dipoles with very weak coupling. Problems in the feeding balun, greatly deteriorating the CP performance at the resonance, are clearly addressed and solved. Detailed parametric studies are given in the final part of this paper.

Wideband Periodic Endfire Antenna With Bowtie Dipoles

A wide-band unidirectional cavity-backed bowtie antenna with stable radiation patterns is proposed in this paper. It is differentially fed by a parallel strip line via a transition from a microstrip line. The corners of the conventional triangular bowtie dipole are rounded to achieve a larger impedance bandwidth. A circular ring, acting as a special reflector, is placed within the cavity, between the ground plane and the bowtie dipole, for stabilizing the broadside radiation patterns over the whole operating band. Numerical simulations and parametric studies are performed to verify the effectiveness of the ring reflector for radiation pattern improvement when it is electrically close to the bowtie dipole. The final design is fabricated and measured. Measured results indicate that the proposed antenna features an impedance bandwidth of 91.4% for SWR les 2, a 7.3-9.5 dBi broadside gain, a total size of 1.56 times 0.325lambda0 2 (lambda0 is the free-space wavelength at the center frequency) and stable radiation patterns over the whole band.