P. C. Sharma

A COMPACT UWB ANTENNA WITH DUAL BAND REJECTION

In this communication, a new compact UWB monopole antenna with dual band rejection is presented. The antenna is designed using FR4 substrate with dielectric constant 4.4, loss tangent 0.02 and a height of 1.59mm. Initially the UWB antenna is designed to obtain a 153% fractional bandwidth from 2.4GHz{21.7GHz. The ground plane beneath the patch is etched out and a rectangular slot is introduced to obtain a broadband matching over the operating frequency range. Later the antenna is modifled to get a frequency notch in the IEEE802.11a and HIPERLAN/2 WLAN operating band (5.15GHz{5.825GHz) to avoid potential interference. A U shaped slot is optimally introduced in the patch to get the desired performance. Finally an L shaped slot is cut from the radiating patch to fllter the frequency band 3.3GHz{3.6GHz, which is WiMAX service band. The antenna parameters are optimized and the efiects of parametric variation on antennas performance are studied and the summary is presented. The antenna is fabricated and measured results are presented. The measured results are in well agreement with the simulated results.

Gain Enhancement of Circular Microstrip Antenna for Personal Communication Systems

This paper introduces the design of an enhanced gain compact circular antenna for personal communication systems (PCS). The antenna is designed to operate at 1.8GHz which shows an impedance bandwidth of 100MHz. The return loss and radiation characteristics of the proposed microstrip antenna are compared with that of the reference antenna, which is the conventional circular antenna. A gain enhancement of 3.8dB is achieved by vertically stacking a circular ring shaped parasitic element. The spacing between the driven patch and parasitic element (h) is optimized to maximize electromagnetic coupling between the two, which results in enhancement of the antenna gain. Parametric study of the proposed antenna is also carried out. The results are validated using two different structure simulation methods based EM simulators viz Finite Integration Technique (FIT) based CST and Method of Moment (MOM) based IE3D. A good agreement is obtained in the results from both techniques which verifies the antenna design and strongly recommend the proposed structure for commercial applications.

A pattern reconfigurable patch antenna with square ring shaped parasite radiator

A new method to reconfigure the radiation pattern of a simple square microstrip patch antenna is presented. A square ring shaped parasitic radiator is electromagnetically coupled with the square shaped patch. The parasitic radiator uses a switch (currently short and open for the proof of concept) in one of its arm to reconfigure its radiation pattern. The antenna is designed at 1.8GHz, and has potential applications in multiple-input multiple-output (MIMO) communication systems. FDTD method based simulation results are presented. The effect of changes in other physical dimension is also discussed.

An equilateral triangular patch antenna with T - shaped notch for enhanced gain

Broadside radiated microstrip patch with enhanced gain has been designed with center frequency of 1.8 GHz. In order to achieve gain enhancement T-notches have been introduced in the sides of equilateral triangular patch antenna. Gain enhancement of 2.9 dB is achieved.

An ultra broadband stacked circular patch antenna

A stacked, three layer circular antenna is presented here which has ultra wide band radiation characteristic. In order to achieve wide bandwidth, proximity coupled circular patches with dual probe feed is used. The resonator parameters are optimized in order to achieve ultra wide band characteristics. Few optimization results are also presented. Return loss, radiation pattern and VSWR over frequency range 1GHz – 30GHz is presented for the best antenna.

Design of a single layer multiband microstrip square ring antenna

The characteristics of a compact, slotted microstrip square ring antenna are investigated. It achieves multiband and wideband functionality through the addition of the circular slots in the dielectric and ground plane of the square ring antenna. The antenna is analyzed in the frequency band of 1 – 30 GHz. The antenna exhibits radiation characteristics in L, S, C, X, Ku, and K bands. Investigations on the radiation characteristics have also been carried out and the results are presented.