This thesis investigates terahertz transmission through finite-size arrays of subwavelength holes perforated in a thin aluminum film modified with a periodic layer of dielectric pegs resting on the hole openings. Samples of differing patterns and numbers of holes were fabricated in a 350 nm thick layer of aluminum on top of a 640 m thick silicon substrate layer. The dielectric peg layer (DPL) consisted of periodically-spaced pegs made out of negative photoresist material. Terahertz time-domain spectroscopy measurements of the transmission was taken both before and after fabrication of the DPL on top of the hole array samples. The results were analyzed and compared to simulation of an infinitely periodic hole array modified with a DPL.