Due to limited voltage supplies in scaled CMOS and the lower amplitude of harmonic generation at frequencies above transistors’ fmax, the radiated power out of a single element around 300GHz is limited to 0.5mW. Generating more power by combining signals from several locked sources on chip to the same on-chip antenna is not efficient due to the high loss of interconnects at these frequencies. Using conventional phased-array transmitter architectures by spacing a 2D array of radiators with a minimum pitch of λ/2 (0.5 mm at 300 GHz) for spatial combining, limits the radiated power density in the chip to 2mW/mm2 and requires very large chips to generate more THz power.

The Solution
We present a new novel approach for generating more radiated THz power out of a chip with a fixed area. By addressing the silicon die as a rectangular Dielectric Resonance Antenna (DRA), each exciting element (RF power source coupled to an electromagnetic excitation) is now considered as a feeding source for the Silicon DRA. Since the power is now combined within the DRA and radiated from it, there is no more need to keep λ/2 spacing between the array sources. In this case, by bringing the sources closer, the die area can be reduced significantly as compared to an area with a half wavelength conventional spacing.

Using Dielectric materials in all various shapes to form a Dielectric Reosnator Antenna provides a compact and efficient way to achieve a high gain and wideband antennas. The low loss in the dielectric material provides excellent radiation efficiency and exciting methods for such DRAs are compatible with planar RF and microwave technogies. Usually the DRA is excited by a coupling the power from a transmission line or pin. The power generation circuits are placed on an adjacent chip and coupling this power to the transmission medium and than to the DRA may result in severe signal loss due to metal, stray radiation and transition. The proposed novel approach is to use the silicon die, already housing the power generation circuits, as the DRA by properly designing its dimensions.

Main Advantages
• Reduced die area compared to conventional spacing
• Tight integration of excitation element with the active power generator
• Efficient radiation of the power to free space.
o This will provide an efficient, compact and low cost solution
 at RF, mm-Wave and THz frequencies.
• High, efficicient power radiator
                
Potential Applications
• Comapact, single chip, wideband, high gain and high efficiency for:
o UWB transmitters
o RADAR frontend circuitry
o Imaging THz spectroscopy and tomography
o Bio-medical 3D imaging devices