Dual‐band RFID tag antenna based on the Hilbert‐curve fractal for HF and UHF applications

Abstract

A novel single-radiator card-type tag is proposed which is constructed using a series Hilbert-curve loop and matched stub for high frequency (HF)/ultra high frequency (UHF) dual-band radio frequency identification (RFID) positioning applications. This is achieved by merging the series Hilbert-curve for implementing the HF coil antenna, and square loop structure for implementing the UHF antenna to form a single RFID tag radiator. The RFID tag has directivity of 1.75 dBi at 25 MHz, 2.65 dBi at 785 MHz, 2.82 MHz at 835 MHz and 2.75 dBi at 925 MHz. The tag exhibits circular polarisation with −3 dB axial-ratio bandwidth of 14, 480, 605 and 455 MHz at 25, 785, 835 and 925 MHz, respectively. The radiation characteristics of the RFID tag is quasi-omnidirectional in its two orthogonal planes. Impedance matching circuits for the HF/UHF dual-band RFID tag are designed for optimal power transfer with the microchip. The resulting dual-band tag is highly compact in size and possesses good overall performance which makes it suitable for diverse applications.

Composite right/left-handed transmission-line based wideband antenna for WLAN, WiMAX and WiFi applications

“…The CRLH-TL unit-cells can be implemented using either surface mount chip components and/or distributed transmission-lines as discussed in [11][12][13][14][15][16][17][18][19][20][21][22][23]. Lumped components are not preferred in antenna designs because they are lossy and have limited discrete values.…”

“…Several techniques have been investigated to reduce the size of such antennas [8]; however such techniques result in increased design complexity that is expensive to implement. To overcome this deficiency antenna realized using CRLH-TL is yielding promising results [9][10][11][12][13][14][15][16][17][18]. Various implementations of CRLH-TLs structures have been reported and demonstrated [19][20][21][22][23].…”

Transformation Optical User-Friendly Interface for Designing Metamaterials

“…For examples, metamaterials have nanostructured media with hyperbolic dispersion for practical applications from subwavelength resolution imaging in the near and far field [1][2][3][4][5], negative refraction [6][7][8], invisibility devices [9] and perfect absorbers [10], to nonlinear switching [11]. Metamaterials with microscopic structures are also proposed for applications of the transmission line and microwave [12] such as the ultra wideband antenna [13][14][15][16][17][18], the leaky-wave antenna [19,20], the resonator [21], the dual-band RFID antenna [22], the coupled-line phaser [23], the magnetless nonreciprocal gyroscopic metasurface [24]. Furthermore, metamaterials are used for an acoustic transformation media [25], or a two-layered isotropic thermal media [26] in a manner not observed in the bulk materials.…”

Planar Antennas for Reliable Multiband RF Communications

“…This necessitates antennas to operate over a wideband [1,2]. Nowadays microstrip integrated technology (MIT) is being increasingly used in the design of antennas for application in wireless communication systems because it offers considerable size reduction, cost effectiveness as it allows easy manufacture in mass production, durability and enables antennas to be configured for mounting on various irregular surfaces [3,4].…”