Mawarni Mohamed Yunus

Design of microstrip antenna for GPS application

This paper presents the design of pentagonal microstrip antenna for dual resonant frequencies at L1 (1.575 GHz) and L2 (1.227 GHz) with right hand circular polarization (RHCP). Designing and optimization processes took place in Zeland IE3D simulation software before the design was printed on RO4003C laminated board. Result of the simulation shows at 1.575 GHz and 1.227 GHz, the antenna has return loss at -18.07 dB and -19.44 dB respectively.

A 2.45 GHz Harmonic Suppression Rectangular Patch Antenna with Circular Polarization for Wireless Power Transfer Application

ABSTRACT This paper presents a 2.45 GHz harmonic suppression rectangular patch antenna with circularly polarized for wireless power transfer applications. The miniaturized proximity-coupled antenna has the advantage of excellent higher harmonic suppression of up to −3 dB at harmonic frequency. This characteristic is achieved by introducing a U-slot and the symmetrical arm of inverted U-stub embedded on the transmission feed line. The overall size of the proposed antenna gives 36% reduction of substrate area as compared to conventional designs. The antenna is designed, optimized, and simulated on FR-4 substrate of dielectric constant 4.3, loss tangent 0.019, and height 1.6 mm offering moderate gain and good axial ratio of 1.48 dB. Details of the simulated and experimental characteristics of the antenna are presented and discussed.

Estimation of interfade duration for Ku- and Ka-band satellite communication system in equatorial Malaysia

Knowledge of the dynamics characteristics of rain fade is important for satellite communication (SatCom) system designs since it determines the system availability as well as provides essential information for the implementation of Propagation Impairment Mitigation Techniques (PIMTs). In particular, the interfade duration due to rain - appear as one of the crucial parameter to provide estimation for the system requirements to recover in time before the next outage. In fact, this is even much more critical in tropical/equatorial region and at high frequencies (Ku-band and above). In this paper, we present an estimation of interfade duration in Ku- and Ka-band by applying the Stratiform-Convective Synthetic Storm Techniques (SC-SST) and a good agreement with measured statistic has been found. The performance of the prediction model in estimating interfade duration characteristic is evaluated quantitatively by means of figure of merit, and the result show RMS error of 0.91 for prediction at Ku-band. In addition, comparison of the SC-SST in equatorial region with the measurement results in temperate area for Ka-band clearly point out significant differences among two regions and also the needs of the measurement results for further validation activities in equatorial area.

Analysis of inter-fade intervals at Ku-band in heavy rain region

This paper aims to present a statistical analysis on inter-fade interval in equatorial heavy rain region based on one year of Ku-band propagation measurement campaign carried out in Universiti Teknologi Malaysia (UTM), Johor, Malaysia. We first present the rain attenuation statistic from both temperate and tropical region (equatorial) followed by analysis on inter-fade intervals for different thresholds as well as their diurnal variation. Statistical knowledge of inter-fade interval has significant impact in designing earth-to-satellite communication system.

Stacked patch antenna harmonic suppression at 2.45 GHz for wireless power transfer

This paper presents antenna harmonic suppression for wireless power transfer systems. It is demonstrated that application of open stub on the feed line, curvature slots and notch at the antenna patch suppressed undesired signals exhibit near second order effectively. The partially ground with a circular slot at ground plane is introduced to minimize the overall patch size. The patch antenna is designed on an FR-4 substrate with εr = 4.7 and 1.6 mm of its thickness. The proposed designs yield -29.536 dB return loss at fundamental modes and suppress all the harmonics until the acceptable range up to -3 dB. The proposed antenna, enhanced the bandwidth about three times and offer moderate gain 4.378 dB and gives advantage whereby the patch antenna can work as radiating and filtering of RF signals in a single module without using a filter circuit which contribute additional insertion loss to the systems.