Development of a Semielliptical Partial Ground Plane Antenna for RFID and GSM-900

A novel compact broadband patch antenna for UHF (ultrahigh frequency), RFID (radio frequency identification), and GSM-900 (global system for mobile communications) band is shown in this paper. The antenna is composed of an ellipse shape annular ring at the patch. The ground plane of the planar antenna is modified with a semiellipse shape slot. The structure can generate substantial amount of current at the feed-line. The geometry of the antenna is evaluated by using HFSS simulation software and deliberated across the paper. Parametric study is exhibited to delineate the response change of the antenna. The antenna has a physical width of 0.24 λ and length of 0.3 λ. It covers a frequency starting from 0.9 GHz to 1.08 GHz. A fractional bandwidth of 18.2% has been achieved from 0.9 GHz till 1.08 GHz. An average gain of 5.5 dBi is achieved at the resonance frequency. The simulated and measured results have good agreement

Near real time ionospheric monitoring system over Malaysia using GPS data: my-iono service

Recently, real time information on the local ionospheric condition is becoming an important need for space and ground based technological systems which are prone to be affected by the local ionospheric state. Knowledge on the impact from the sun activity to the equatorial and low latitude ionosphere is crucial for research and development purpose in all developing nations which are relying on space-based technology systems such as the Global Navigation Satellite System (GNSS). As the first action step to achieve deeper understanding and hands on experience on real time ionospheric monitoring, the National Space Agency of Malaysia (ANGKASA) in collaboration with Universiti Teknologi Malaysia (UTM) has developed the first near real time ionospheric and space weather monitoring system for Malaysia (My-Iono) in year 2015. This web-based platform operates based on the National R&D GPS Continuously operating reference station network (NRC-net). The system runs based on a locally derived algorithm called Equatorial Ionosphere Index (EIX). The EIX was formulated based on 10 years (2004 to 2013) GPS derived empirical Total Electron Content (TEC) data obtained frpm 78 My-RTKnet stations around Malaysia. The fundamental of My-Iono Service consists of vertical TEC maps with a latency of ∼ 2 mins over Malaysia and information on the current ionospheric status; Normal, Medium and Severe, time series of Mean VTEC for station specific, time series of RAte of Change of tEc (RACE) for station specific and time series of Ionospheric Zenith (Iz) Delay for station specific estimated in near real time using GPS observations. This paper presents on the development of My-Iono Service in terms of system design and architecture

Assessment of ionosphere models at Banting: Performance of IRI-2007, IRI-2012 and NeQuick 2 models during the ascending phase of Solar Cycle 24

The International Reference Ionosphere (IRI) and the NeQuick models have been recognised as the international standard for specifying Earth’s ionospheric parameters. However, the performance of these ionosphere models needs to be validated due to data scarcity from South-East Asian region for model development. This work presents the performance evaluation of IRI-2007, IRI-2012 and NeQuick 2 in estimating ionospheric Total Electron Content (TEC) at Banting (Geographic: 2.78°N, 101.51°E; Geomagnetic: 7.11°S, 173.77°E). For this purpose, TEC values estimated from these models have been compared with TEC values derived from dual-frequency Global Positioning System (GPS) data for the year 2011 (ascending phase of Solar Cycle 24). The results show that equatorial TEC exhibits semi-annual, annual, and seasonal variations with maximum values appearing during equinoctial months and minimum during solstitial months. Generally, ionospheric TEC produced by IRI and NeQuick 2 models are in good agreement with observed TEC. For diurnal variation, the IRI-2007 and NeQuick 2 models show good agreement during post-noon and post-midnight, respectively. Good correlation is observed during noon-time for all models. Disagreements between ionospheric models and observed TEC are found during post-sunset and post-midnight periods, with TEC deviation in the level of 11–14 TECU can be anticipated at 95% probability. On the other hand, TEC calculation from IRI-2012 is better than IRI-2007 and NeQuick 2 for monthly variation. All models score correlation coefficient above 0.9 with the highest correlation noticed during solstitial months. TEC deviation above 10 and up to 15 TECU can be expected in October with 95% probability. Overall, this work reveals that IRI and NeQuick 2 models are capable of predicting TEC with good correlation in most cases