Simulation of wirelessly passive SAW ID-tags/sensors using VHDL-AMS

SAW devices can be used in a wide range because of their intriguing properties, such as their ability to store signal energy contained in acoustic waves for a relatively long time, their adaptability to semiconductor producing technology. Since the last decade, SAW scientists have shown great interest in wireless readable identification (ID) tags and sensors. Besides the general properties, SAW ID tags and sensors can work with no battery or wiring, withstand extreme temperatures and work reliably and maintenance-free over decades even in harsh industrial environments. Since the flip-chip technology became applicable to SAW devices, it was proposed to use this technology for bonding SAW devices onto silicon application specific integrated circuits (Si-ASIC). VHDL-AMS (VHSIC hardware description language analog mixed digital) is an extension to VHDL, which was used in ASIC design to support the description and simulation of analog and mixed-signal circuits and systems. Any model valid in VHDL 1076 is valid in VHDL-AMS and yields the same simulation results. In this paper, a method to simulate SAW ID tags/sensors using VHDL-AMS is proposed. We have used the VHDL-AMS simulator (advance ms produced by Mentor Graphics) to simulate SAW ID tags and sensors produced on 128°YX lithium niobate substrates in radio frequency range.