A frequency quadrupler comprises a balanced topology which increases broadband odd harmonic suppression. The frequency quadrupler is constructed in a cascode configuration which is a two-stage amplifier composed of a transconductance amplifier followed by a current buffer. The cascode is constructed with common emitter (CE) and common base (CB) stages which further improves the multiplier frequency response. The cascode configuration enables a notch filter to be placed between the common emitter and common base stages to reduce 2nd harmonic generation and thereby increase 4th harmonic output power, generation efficiency and conversion gain. To cancel 4th harmonic components at the input that may destructively interfere with the output signal, capacitors are placed at the input of the common emitter stage, which in conjunction with the parasitic base wire inductance, form a notch filter to short the 4th harmonic.