Novel Bow-tie–AMC Combination for 5.8-GHz RFID Tags Usable With Metallic Objects

Abstract

A novel combination of coplanar waveguide (CPW)-fed double bow-tie slot antenna and artificial magnetic conductor (AMC), which meets the requirements of a 5.8-GHz SHF RFID tag antenna usable on metallic objects, is presented. The manufactured prototype is characterized in terms of return loss, gain, and radiation pattern measurements in an anechoic chamber, both alone and on a metallic plate.Index Terms-Antenna, artificial magnetic conductor (AMC), coplanar waveguide (CPW), radio frequency identification (RFID).

Passive UHF RFID Tags with Specific Printed Antennas for Dielectric and Metallic Objects Applications

“…In the case of the RFID tag, this proximity is the maximum possible as the tag is attached to the object. In the literature, various configurations of antennas destined for metallic hosts have been proposed as, inverted-F type [30], antennas modeled by loop and open and shorted printed strip lines [31], bow-tie patches connected through metallic pins to the back plane [32] or bowtie slot type combined with Artificial Magnetic Conductor (AMC) [33], meander-type [34] or metamaterial structured antennas [35], patches, inset fed by open stub printed line at which the IC is mounted [36], patch antenna with proximity-coupled feed with line shorted at its end [37] and coupled shorted patches fed by printed loop for the IC hosting [38]. The microstrip type is superior to the printed type due to the fact the effectiveness of the printed models are strongly reduced when they are positioned very close to metallic surfaces and moreover large shifting of their resonance frequency occurs.…”

“…11b) is judged as sufficient. The proposed antenna has advantages as a) simple structure compared with other ones with metamaterial [33] or AMC lattices [31], shorting pins [29], [30], [35], [36] etc. ; and b) a performance as good as other tags presented in the literature.…”

Behavioral study of a CPW-fed dual-band antenna combined with a polarization dependent AMC

“…Once the AMC´s behavior is characterized, the integration of the periodic structure with the CPW-fed dual band antenna is investigated [5]. Accordingly, an arrangement of 11x8 unitcells has been combined with the CPW-fed dual band antenna (as the antenna has no ground plane below the dielectric substrate, the AMC's unit-cells below the antenna have been removed) and the resulting design is analyzed in terms of return loss and radiation properties.…”

Small sized uniplanar artificial magnetic conductor

“…The AMC angular stability is a major concern if the periodic structure is used as planar antenna ground plane [8], [13]. So, depending on the fields radiated by the antenna, the radiation properties can be enhanced in either 6.2GHz or 8.5GHz frequency band.…”

“…Traditionally, at microwave frequencies, the AMC structure has a unit-cell size of about half to quarter wavelength [7], making the overall AMC prohibitively large, if it is used as backing plane for antennas [8]. It is a really challenge for designers to obtain a low frequency AMC structures because in term of its wavelength, the unit-cell can still be large.…”