Novel tapped feed structures for extremely small normal mode helical antennas

Author

Jung, Woong Hyun ; Michishita, Naobumi ; Yamada, Yoshihide

Author_Institution

Nat. Defense Acad.

fYear

2006

fDate

9-14 July 2006

Firstpage

1047

Lastpage

1050

Abstract

Extremely small normal mode helical antennas (NMHA) for RFID tags were developed. By introducing folded structures, antenna efficiencies of -5 dB and -1.5 dB were achieved in antenna sizes of 0.025 wavelength and 0.05 wavelength, respectively. However, antenna input resistances were very low such as 5 ~ 8 Omega. Impedance matching structures were requested. In this paper, novel impedance matching structures are proposed. A tap feed is composed around a helical wire. A very compact matching structure is accomplished. Excellent impedance matching capabilities to 50 Omega coaxial cables are ensured through numerical and experimental studies

Keywords

antenna feeds; helical antennas; impedance matching; radiofrequency identification; 50 ohm; RFID tags; antenna input resistances; coaxial cables; extremely small normal mode helical antennas; folded structures; helical wire; impedance matching structures; tapped feed structures; Antenna feeds; Antenna measurements; Atmospheric measurements; Coaxial cables; Electrical resistance measurement; Helical antennas; Impedance matching; Impedance measurement; Temperature sensors; Wire;

fLanguage

English

Publisher

ieee

Conference_Titel

Antennas and Propagation Society International Symposium 2006, IEEE

Conference_Location

Albuquerque, NM

Print_ISBN

1-4244-0123-2

Type

conf

DOI

10.1109/APS.2006.1710713

Filename

1710713