A systematic method for designing an RFID label antenna is shown in the form of a ?¬‚ow
chart in Figure 4.15. This methodology is an expansion of the approach to tag antenna
design found in Rao et al. (2005).
Once the antenna requirements are established by extracting them from the required
application scenario, it is possible to look at the types of materials suitable for constructing
the antenna in terms of cost constraints and operational conditions of the application. It is
then important to determine the input impedance of the RFID IC in a selected package at
the threshold of operation; this might be obtained from the manufacturer or may be
obtained by direct measurement using a network analyzer.
Selecting a suitable antenna type is now possible; there are numerous designs available
such as simple loops, dipoles, meander lines, spirals, and patch antennas. However, if an
antenna parametric study reveals that it is not possible to obtain the required input
impedance with a standard design within the design constraints, a designer is required
to think more imaginatively.
Identify the antenna requirements based on the application
Identify material suitable for constructing the antenna
Obtain the input impedance of the RFID IC to be used
Identify suitable antenna types, its dimensions, and
impedance properties if possible
Consider a one-element or two-element matching circuit
Integrate the matching circuit elements to the antenna
Does varying physical dimensions
yield a suitable conjugate match
to the RFID IC impedance?
Construct prototypes and measure performance
Perform simulations, measurements, and optimizations
Does the antenna meet design
requirements?
Ready for
manufacture
Yes
No
FIGURE 4.
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