NOVELTY - The system has a substrate supporting a monolithically integrated circuit e.g. transmitter chip (100), with a radio frequency (RF) transmitter (110) comprising an on-chip antenna (120). A ground plane is overlied on the on-chip antenna. Another substrate includes a microstrip patch antenna overlying the ground plane and spaced by a gap. An aperture i.e. slot, is defined in the ground plane for electromagnetic coupling of the on-chip and patch antennas, where aperature length is selected relative to the patch antenna size to reduce backward radiation from the slot in the ground plane.    USE - Radio frequency (RF) transmitter system for use with a radio frequency receiver (claimed) for voice and data communications for system on-chip (SoC) and system-on-package (SoP) such as wireless local area network (LAN) and sensor systems in an industrial application, biomedical application or space application.    ADVANTAGE - The on-chip antenna feeds a low temperature co-fired ceramic (LTCC) patch antenna through aperture coupling, thus negating the need for radio frequency (RF) buffer amplifiers, matching elements, baluns, bond wires and package transmission lines, and increasing gain and range of the module with respect to the on-chip antenna without deterioration of circuit performance and power consumption. The system is fabricated using standard complementary metal-oxide-semiconductor (CMOS) technology for operation in 5 giga hetz unlicensed national information infrastructure (U-NII) band, so that wireless devices and sensor systems are miniaturized. The system is miniaturized, and inexpensive. The slot length is selected relative to the patch antenna size to minimize backward radiation from the slot in the ground plane. The transmitter chip is housed without loss.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a radio frequency receiver, comprising a monolithically integrated radio frequency receiver circuit with an on-chip antenna.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram and photomicrograph of a system on-chip implementation of a radio frequency wireless transmitter integrated circuit with on-chip antenna and a radio frequency wireless receiver integrated circuit with an on-chip antenna.    Wireless transmitter/receiver system (10)    Transmitter chip (100)    On-chip antenna (120, 220)    Active oscillator transmitter circuitry (130)    Receiver chip (200)