Study of graded composite (LDPE/TIO2) materials as substrate for microstrip patch antennas in X-band

TiO₂ (titania) reinforced low density polyethylene (LDPE) composite is studied as substrate for microstrip patch antenna that is to be used in microwave X band (8 GHz to 12 GHz). Physical, thermal and microwave characterization of the composite is done to confirm the applicability of the composite material as substrate for microstrip antennas. Microstrip antenna with rectangular radiating patch is fabricated on composites with different volume fraction (VF) of filler in polymer as substrate. S11 measurements are carried out on the antenna designed on different substrates using vector network analyzer. To increase the operational bandwidth of the antenna three layer grading of the composite substrate is done. The bandwidth and S11 parameter performance of the antenna is found to be improved by using graded composite as substrate material. Enhancement of directivity is observed for graded substrate as compared to ungraded substrate.