This paper investigates a switchable dual-band low noise amplifier design that can operate at X-band and Ka-band using monolithic SiGe heterojunction bipolar transistors (HBT) technology. The LNA is based on a single stage cascade common emitter amplifier with emitter degeneration. Diode connected HBT switch with series-shunt configuration has been utilized for its excellent broadband switch characteristic encompassing X- to Ka-band frequency spectrum. The total switchable dual band LNA dimension is 1.05 × 0.98 mm², consuming 33 mA from 1.2 V supply (39 mW). To our knowledge, this paper is the first one to discuss feasibility of SiGe integrated switchable dual band LNA at X band and Ka band.