Design and Modeling of a Compact Partially Transmissible Resistor-Free Absorptive Frequency Selective Surface for Wi-Fi Applications

A compact partially transmissible absorptive frequency selective surface (AFSS) which requires neither surface mount device resistors nor resistive ink is proposed in this communication. The resistor-free AFSS utilizes the lossy characteristic of FR-4 substrate material to achieve the absorption property. The method to efficiently model the AFSS based on physical phenomena has been thoroughly discussed, by which the effect of substrate loss can be predicted accurately. An equivalent circuit model is also presented, and its predicted result agrees well with the full-wave simulation. Furthermore, the fabrication and measurement are also conducted to demonstrate the feasibility of resistor-free AFSS. The highest absorption rate of the AFSS is designed around 2.46 GHz, while at least half-power transmission is guaranteed below 1 GHz. These electromagnetic functions as well as the low fabrication cost and complexity make the resistor-free AFSS a promising candidate for advanced packaging and shielding of mixed signal system.