52 INTRODUCTION In the context of satellite communications (SATCOM), the term narrowband (NB) generally refers to the ultra-high-frequency (UHF)-, L-, and S-bands, where available bandwidth is limited compared to the higher-frequency bands. These lower-frequency bands in the 300-MHz to 4-GHz range are attractive to the DoD because of their better penetration into buildings and through foliage a...

The ultra high frequency (UHF) band spectrum will likely be congested in near future since the next generation wireless as well as Radio Frequency Identification (RFID) system users will witness the use of UHF band technology with increased demand of bandwidth, bit rate, frequency spectrum and power consumption. The alternate solution is the use of millimeter-wave band technology. It is possibl...

Bu çalışmada, envanter yönetimi amacıyla düşük maliyetli ve esnek kullanıma uygun ultra yüksek frekanslı (UHF), radyo frekansı ile tanımlama (RFID) sistemi gerçekleştirilmiştir. Oluşturulan sistem envanterde bulunan ürünlerin güvenliği izinleri tek bir noktadan etkin şekilde sağlanmıştır. UHF RFID sistemine ait iki adet uygulama noktası oluşturulmuştur. Bunlardan birincisi, kullanıcı izinlerini...

The Wallops 18-Meter diameter UHF-Band and the Morehead State 21-Meter diameter current S-band and future XBand and UHF-Band CubeSat Groundstations answer a growing need for high data rate from CubeSats over government licensed frequencies. Ten years ago, when CubeSats began, they were nothing more than simple science experiments, typically consisting of a camera and a low data rate radio. The ...

A new concept to design thin directional broadband antennas on EBG or HIS surfaces is proposed. Using our proposed concept an octave or more bandwidth is obtained with fairly thin EBG structures even at UHF frequencies allowing low profile antenna design and development. At the heart of the proposed scheme lies the concept of a non-uniform aperiodic EBG surface where the EBG patch size and thei...

This paper describes an antenna system combining Global Navigation Satellite System (GNSS) with Iridium satellite communications and UHF 225-512 MHz communications on a handset to provide an integrated Communications Navigation (Comm/Nav) antenna. The GPS/GNSS/Iridium antenna is a folded Quadrifilar Helix Antenna (QHA) with novel features which improve frequency coverage compared to existing QH...

On 5 July 2005, simultaneous observations of Polar Mesosphere Summer Echoes (PMSE) were made using the EISCAT VHF (224 MHz) and UHF (933 MHz) radars located near Tromsø, Norway and the ALWIN VHF radar (53.5 MHz) situated on Andøya, 120 km SW of the EISCAT site. During the short interval from 12:20 UT until 12:26 UT strong echoes at about 84 km altitude were detected with all three radars. The r...

Each year, about 76 million people contract a food borne illness in the United States; about 325,000 require hospitalization; and about 5,000 die. Tracking goods throughout the food supply chain increases the efficiency of recall of tainted goods and thus will help reducing food borne illness. Passive UHF RFID has been widely accepted to be a technology capable of increasing supply chain effici...

Along with rapid development of sensing and communication technology, Internet of Things (IoTs) has enabled a tremendous number of applications in health care, agriculture, and industry. As the fundamental element, the wireless sensing node, such as radio tags need to be operating under micro power level (e.g, 100 μW, Pico radio) for energy autonomy. The evolution of electronics towards highly ...