Design of stacked wafers AMC at 920 MHz for metallic object detection in RFID application

Abstract

Artificial Magnetic Conductor, AMC is introduced into RFID application to overcome the problem of metal object detection. The AMC act as the Perfect Magnetic Conductor, PMC exhibits a reflectivity of +1 (in-phase reflection). In this paper, the stacked wafers AMC structure is designed to operate at 920 MHz frequency. The proposed stacked wafers AMC is an evolution from the basic square patch AMC. By introducing different size of slots into the square patch will help to reduce the frequency hence increase the bandwidth of the reflection phase. Another method to increase the bandwidth is by increasing the thickness of the structure. For the single cell of stacked wafers AMC proposed in this paper, the simulated bandwidth is 3.5% with reduced size of 45.56% than the square AMC. An optimized structure of 3x2 stacked wafers AMC give better return loss = -21.8 dB and gain = 3.04 dB with total efficiency of 82.3%.

Design of Circularly Polarized Tag Antenna With Artificial Magnetic Conductor for on-Body Applications

“…As the AMC is miniaturized, the resonance bandwidth becomes narrow. Therefore, a stacked AMC substrate was proposed in [5] to increase the bandwidth. Smart clothing has been rapidly developing in recent years Researchers have used diverse textile materials and analyzed the effects of bent AMCs [6,7].…”

Enhancing the angular stability of artificial magnetic conductors through lumped inductors

“…Therefore, observing the expression of the reflection coefficient (1) and taking into consideration the previous remarks, it is obvious that the main limitations of AMCs are in the bandwidth and the angular stability. The bandwidth limitations have been studied in many articles using multiresonance structures [7], [8], [18]- [19]. Some solutions are to stack several layers [18] or using unitcells with close resonances [7].…”

“…The bandwidth limitations have been studied in many articles using multiresonance structures [7], [8], [18]- [19]. Some solutions are to stack several layers [18] or using unitcells with close resonances [7]. However, not so many contributions deal with the angular stability of AMCs [1]- [4], [13], [20]- [22].…”