Quick Estimation of Rectangular Patch Antenna Dimensions Based on Equivalent Design Concept

This letter presents a new method for quickly estimating the physical dimensions of a rectangular microstrip antenna (RMSA). This is based on the newly introduced concept of “Equivalence of Design” for RMSA. Two designs are said to be equivalent if they result in the same resonance frequency. This is an outcome of Bhatnagar's postulate. It relates the classical extension in length ΔL with the length and width of the patch apart from the substrate thickness. This letter emphasizes the importance of substrate thickness normalized with respect to guided wavelength. This is termed as the “H” parameter. For RMSA, this is the key parameter rather than the individual parameters-dielectric constant (εr), substrate thickness (h), or resonance frequency (f0). A new parameter-the scaling factor (Ψ)-has been introduced and defined. Based on these, transformation laws have been put forward. These can be used for quickly estimating the RMSA design parameters from a “known good design.” The laws have been verified by estimating physical parameters of RMSA and then calculating its resonance frequency. This has been repeated for several hundred designs. The matching has been excellent. Simulation and measurement results of a known good design (Design1) and one of the transformed designs (Design3) are also presented. The results of the transformed design are in good agreement with those of Design1 considering fabrication and measurement tolerances.