This paper demonstrates an 8-element phased array receiver in a standard 0.18-mum SiGe BiCMOS (1P6M, SiGe HBT ft ap 150 GHz) technology for X- and Ku-band applications. The array receiver adopts the All-RF architecture, where the phase shifting and power combining are done at the RF level. With the integrations of all the digital control circuitry and ESD protection for all I/O pads, the receiver consumes a current of 100 ~ 200 m A from a 3.3 V supply voltage. The receiver shows 1.5 ~ 24.5 dB of power gain per channel from a 50 Omega load at 12 GHz with bias current control, and an associated NF of 4.2 dB (@ max. gain) to 13.2 dB (@ min. gain). The RMS gain error is < 0.9 dB and the RMS phase error is < 6deg at 6-18 GHz for all 4-bit phase states. The measured group delay is 162.5 plusmn 12.5 ps for all phase states at 6-18 GHz. The RMS phase mismatch and RMS gain mismatch among the eight channels are < 2.7deg and 0.4 dB, respectively, for all 16 phase states, over 6-18 GHz. The 8-element array can operate instantaneously at any center frequency and with a wide bandwidth (3 to 6 GHz, depending on the center frequency) given primarily by the 3 dB gain variation in the 6-18 GHz range. To our knowledge, this is the first demonstration of an All-RF phased array on a silicon chip with very low RMS phase and gain errors at 6-18 GHz. The chip size is 2.2 times 2.45 mm2 including all pads.