A novel system-in-package (SiP) implementation is presented for a transmitter (TX) module which makes use of electromagnetic coupling between the TX chip and package antennas at 5.2 GHz. The TX chip is realized in 0.13 mum CMOS process and comprises an on-chip antenna. This on-chip antenna serves as the oscillatorpsilas inductor as well. The TX chip is housed in a low temperature co-fired ceramic (lTCC) package with a patch antenna. The on-chip antenna feeds the LTCC patch antenna through aperture coupling, thus negating the need for RF buffer amplifiers, matching elements, baluns, bond wires and package transmission lines. This first ever combination of onchip and LTCC antennas increases the gain of the module by 32 dB and range by 23 m with respect to the on-chip antenna alone, without deteriorating the circuit performance and power consumption.