This paper presents the design and finite difference time domain (FDTD) modeling of millimeter wave aperture coupled microstrip antenna that can be realized as a on chip antenna in wireless sensor nodes. At millimeter wave frequency, antenna form factor is very low and hence integration of this antenna with the transceiver components as a single system on-chip, minimizes power consumption and system cost. Offchip antenna increases the size of the sensor node and raises the system cost. The proposed antenna contributes impedance bandwidth of 3 GHz (59 GHz - 62 GHz) and maximum gain of 6.8 dBi. The proposed antenna occupies an area of 1500 μm × 2000 μm on a RT Duroid substrate of dimension 3000 μm × 3000 μm × 1500 μm. Due to very low antenna form factor, the proposed antenna along with the transceiver and sensor components can be integrated into a single system on chip with less system cost for wireless sensor networks. © 2005 - 2012 JATIT & LLS. All rights reserved.