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Why is it important that the impedance of an RFID antenna interrogator and cable be matched?
Proper impedance match between the antenna and the chip is crucial in RFID tag design. It directly influences RFID system performance characteristics such as the range of a tag. It is known that an RFID microchip is a nonlinear load whose complex impedance in each state varies with the frequency and the input power.
What is the limitation of RFID?
Following are the disadvantages of RFID: ➨Active RFID is costly due to use of batteries. ➨Privacy is a concern with the use of RFID on products as it can be easily tapped or intercepted. ➨RFID devices need to be programmed which requires enough amount of time.
What is RFID antenna?
An RFID system consists of three parts: a scanning antenna, an RFID tag which includes all of the information about a product, and a reader which decodes and interprets data on a tag. These radio waves are picked up by the antenna and send to the reader which decodes the waves as digital information.
How is the antenna impedance of a RFID reader determined?
A schematic of a typical antenna circuit is given in Figure 1. The antenna trace width together with the trace spacing, will determine the antenna impedance and Q respectively. Figure 1. RFID Antenna (Typical) SLOA135A–May 2009–Revised September 2013Antenna Matching for the TRF7960 RFID Reader1 Submit Documentation Feedback
Do you need a three element antenna match?
A three element match is recommended as it allows the designer to select the required antenna quality factor, Q, for the application. The PCB design used in this application is based on FR4 material, Er = 4.5, with a material thickness of 0.062 inches. The board design is 2 layer design (layer 1 top, & layer 2 bottom), with 2 oz copper.
What kind of capacitor is used for antenna matching?
The final matching element is a 56- pF capacitor, which rotates the impedance from Imp 3 to Imp 4 (46.6 + j0.3). This capacitor is split into two parallel caps (47 pF + 10 pF) to allow fine tuning of the antenna frequency while also reducing component parasites.