Objective To address the trade-off between bandwidth extension and manufacturability in dual-band frequency selective surface (FSS), a bandwidth extension method based on stub-loaded structures is investigated.

Method First, the main factors causing the above trade-off in conventional bandwidth extension methods are analyzed. Second, the effect of stub loading on FSS electromagnetic characteristics is investigated, such as the resistance properties, shapes and quantities of the loaded stubs. Third, the first and second passbands of FSS are extended by applying stub loading to the grid and gap regions, respectively. The effectiveness of this approach in mitigating the trade-off is examined in detail.

Results Simulation and measurement results show that stub loading technique increases bandwidth by 48.8% in the first band and 23.2% in the second band compared to traditional methods.

Conclusion It is shown that stub loading can effectively reconcile the trade-off between bandwidth extension and machinability in multiband FSS, offering theoretical guidance for engineering applications.