N. Anantrasirichai

Rectangular patch antenna with inset feed and modified ground-plane for wideband antenna

This paper presents the technique for increasing bandwidth of rectangular patch antenna from 0.88 GHz (7.76 - 8.64 GHz) to 6.75 GHz (3.49 - 10.24 GHz). This technique use inset feed patch antenna with modified ground plane for achieved widest bandwidth. We will propose three types of rectangular patch antenna: the simple rectangular patch fed by microstrip line, inset feed rectangular patch and inset feed rectangular patch with modifies ground plane. The final simulation result show that the lower edge of frequency is moved down from 7.76 GHz to 3.49 GHz and the higher edge of frequency is shifted up from 8.64 GHz to 10.24 GHz, which is the one selection for increasing bandwidth of rectangular patch antenna for wideband. Details of the increasing bandwidth of microstrip patch antenna are described, and simulation results for obtained wideband performance are presented by using IE3D Zeland software.

Design CPW Fed Slot Antenna for Wideband Applications

In this paper, a CPW-fed slot antenna for wideband application was designed and simulated. In order to examine the performances of this antenna, a prototype was designed at frequency 2.4GHz and simulated with various width of slot antenna in both sides for input impedances matching and simulated by IE3D software package of Zeland. The simulation result of bandwidth is 1.65GHz (2.1{3.75 GHz) which covers the standard frequency of IEEE 802.11 b/g (2.4{2.4835GHz) and Wimax (2.3{3.6GHz). With these performances, the proposed antenna can be used in wideband applications. DOI: 10.2529/PIERS061009084055

Inversed e-Shape slot antenna for WLAN applications

This paper present an inversed e-shape slot antenna for wireless LAN applications. The antenna is designed for dual frequency band 2.38-2.5 GHz and 4.8-6.16 GHz of resonance frequency 2.44 GHz and 5.68 GHz, respectively, which can support WLAN applications coverage IEEE 802.11b/g (2.4 -2.4835 GHz), IEEE 802.11j (4.90-5.091 GHz), IEEE 802.11a (5.15-5.35 GHz), and Wimax of IEEE 802.16d (5.7-5.9 GHz). The bandwidth at low resonance frequency and high resonance frequency are 0.12 GHz and 1.36 GHz, respectively. The simulation results of inversed e-shape slot antenna are analyzed by using method of moment (MoM) from IE3D software.

Tri-Band Rectangular Spiral Slot Antenna with L-Shaped Slot Antenna for WLAN and Radar Applications

Tri-band rectangular spiral slot (RSS) antenna with an L-shaped slot antenna insertion is introduced in this paper. The antenna was designed on the substrate with 2.2 of dielectric constant and 1.575 mm of thickness. FDTD method was adopted to evaluate the proposed antenna characteristics A rectangular spiral slot antenna was designed to support dual-frequency at 2.44 GHz and 8 GHz. An L-shaped slot antenna was inserted to obtain more resonant frequency at 5.2 GHz. The simulation results revealed that the proposed antenna could be used to support tri-band of frequency which is compatible to IEEE 802.11a or HIPERLAN (5.2 GHz) standard, IEEE 802.11b/g (Wi-Fi 2.44 GHz) standard and 8.0 GHz satellite or radar communications

e-Shaped Slot Antenna for WLAN Applications

This paper present an e-shaped slot antenna for wireless communications. The antenna is designed for dual frequency band 2.4{2.52GHz and 4.82{6.32GHz, which support WLAN communications coverage IEEE 802.11b/g (2.4{2.4835GHz), IEEE 802.11j (4.90{5.091), IEEE 802.11a (5.15{5.35GHz), and IEEE 802.16d (5.7{5.9GHz). The bandwidth at low reso- nant frequency and high resonant frequency are about 0.12GHz and 1.5GHz, respectively. The simulation results of e-shaped slot antenna are analyzed by using Method of Moment (MoM) from IE3D Software. DOI: 10.2529/PIERS061007105447

Design Narrow Slot Antenna for Dual Frequency

Abstract| The narrow slot loop antenna and linear slot antenna fed by microstrip line are designed for dual frequency at 2.44 GHz and 5.25 GHz on the standard of IEEE 802.11b/g (2.4{2.4835 GHz), IEEE 802.11j/a (5.15{5.35 GHz), and IEEE 802.16d (5.7{5.9 GHz).

A robust variable step-size LMS-like algorithm for a second-order adaptive IIR notch filter for frequency detection

The best adaptive algorithm requires fast convergence speed, low variance, unbias and low steady-state mean square error (MSE) in both low and high signal-to-noise ratio (SNR) situations. We have proposed a robust variable step-size LMS-like algorithm (VS-LMS-L) for a second-order adaptive IIR notch filter for frequency detection in radar, sonar and communication systems. This algorithm is compared with the conventional LMS-like algorithm called the plain gradient algorithm (PG). The time-varying step-size /spl mu/(n) is adjusted by using the square of the time-averaged estimate of autocorrelation of the present output signal y(n) and the past one y(n-1). This technique can reject the effect of the uncorrelated noise sequence on the step-size update, resulting in a small MSE due to the small final /spl mu/(n). Moreover, this algorithm can also improve the convergence speed by comparison with the PG at the same MSE value.

Bandwidth Enhancement of CPW-Fed Slot Antenna with Inset Tuning Stub

The coplanar waveguide fed slot antenna with inset tuning stub is proposed for WLAN and WiMAX applications. This antenna consists of a rectangular patch element embedded with a tuning stub fed by CPW feed line. The antenna is designed for match impedance with 50 ohm of characteristic impedance of transmission line by using inset tuning stub for wideband matching. The simulation and measurement results show good agreement operation, which range of bandwidth can be achieved from 1.65 GHz - 6.35 GHz or 117%, suitable for applications to cover 2.4/5.2/5.8 GHz of WLAN bands and 2.5/3.5/5.5 GHz of WiMAX bands. The characteristics of antenna are proposed and analyzed for return loss, bandwidth, current distribution, voltage standing wave ratio and far field radiation patterns.

Double rectangular slot loop antenna for dual frequency

This paper presents the technique for reducing size of double rectangular slot loop antenna fed by microstrip line for dual frequency. The two difference configurations of double rectangular slot loop antenna are proposed for comparison on bandwidth and size of antenna. These antennas are designed for dual frequency support WLAN system coverage IEEE 802.11b/g (2.4-2.4835 GHz), IEEE 802.11j (4.90-5.091), IEEE 802.11a (5.15-5.35 GHz), and IEEE 802.16d (5.7-5.9 GHz). The PCB-FR4 substrate with dielectric constant (epsivr) 4.5 of thickness 1.6 mm is chose for low cost. The simulation results of these slot antennas are analyzed by using method of moment (MoM) from IE3D software. In this case, the result of bandwidth for low frequency and high frequency of one antenna are 11.29% and 62%, and other are 6.1% and 75.5%, respectively. The size with ground plane of double slot loop antenna can be reduced 12.9% or can be reduced size of double slot loop antenna about 21.5% when set the new inner conductor.

The reduction of gradient noise in gradient-based algorithm by using variable step-size technique

This paper proposes a different approach to control step-size adaptation. The objective is to ensure large step-size when the algorithm is far from the optimum with step-size decreasing as we approach the optimum. The proposed algorithm achieves this objective by employing the output signal energy to control step-size update. In the early stage of adaptation the estimate of the output signal energy is large, resulting in a large step-size. As we approach the optimal, the output signal energy approaches zero, resulting in a small step-size. This provides the fast convergence due to large initial step-size while ensuring low gradient noise due to the small final step-size, resulting in low variance of the filter coefficient.