Planar inverted F-antenna are playing an important role in wireless communication systemsrnbecause of their many advantages like light weight, low profile, low cost, easy integration withrnplanar structure and easy fabrication. The main objective of this thesis is to discuss therncharacteristics of PIFA antenna using different change of design parameters such as shorteningrnplate width, ground plane width ground plane length, patch width, and patch length and height.rnThe design issues include PIFA antenna dimensions, feeding techniques and various polarizationrnmechanisms whereas the performance issues include voltage standing wave ratio, radiationrnpattern, directivity and specific absorption rate. In this thesis, both single element and four byrnfour elements of PIFA antenna at Ka-band are designed using the CAD-FEKO simulationrnsoftware. To design it, standard formulas are used to calculate different parameters of thernantenna. The proposed antenna is designed to work at 28GHz frequency band and simulationrnresults shows that 4.66 dB and 7.63dB of directivity for single element and four by four elementsrnof PIFA antenna were attained respectively and also SAR values of 2.26w/kg for single elementrnand 0.613w/kg for four by four elements design were attained. To achieve all the above resultsrnboth single element and planar array of PIFA antenna were designed with micro-strip linernfeeding based on quarter wave impedance matching technique using CAD-FEKO simulationrnsoftware.