This paper presents a 100-120-GHz pulse transmitter chip with a 54×24 on-chip loop antenna array for the purpose of beam-formability in portable millimeter-wave (mm-wave) active imaging applications. We present a new idea for silicon-based mm-wave pulse beam-forming by using voltage-varied CMOS inverter chain. This 4-mm×4-mm transmitter chip is designed and fabricated in a 2.5-V 0.25-µm 4-metal-layer Si-Ge Bi-CMOS process. The 30-µm × 30-µm loop antenna located on the top-metal layer operates as an coil in an integrated mm-wave pulse generator. Each of on-chip pulse generators employing under-damped/over-damped conditions to produce mm-wave pulses includes an R-L-C circuit, a bipolar junction transistor (BJT) operated as a switch and a CMOS inverter chain circuit for shaping the rising edge of the input clock. Simulation results by ADS 2009 and HSPICE show that loop antenna' inductance and resistance at 80-120-GHz are 51pH and 3Ω, respectively. A simulation performance of an integrated 13×6 loop antenna array illustrates the variation of maximum radiation angles depending on different phase values between array's elements. By using an mm-wave power meter, a 90-140-GHz standard horn antenna and a Schottky diode detector, several measured radiation patterns of this loop antenna array chip are achieved. From the measurement result, we demonstrate the possibility of an integrated mm-wave pulse generator for the purpose of beam-forming by changing power supplies of inverter chains.