The development of single-chip transmitters and receivers is hindered by several obstacles. The main difficulties include the low quality factor of MMIC filters, limited output power of solid state devices at millimeter-wave frequencies, and poor frequency stability of monolithic oscillators. This research investigates novel techniques to overcome these challenges. The scope of work includes proposal of new circuit structures and techniques, theoretical analyses, MMIC realisations and experimental verifications with measured results. To reduce filtering requirements, single-ended and single-balanced resistive mixers, utilising a unique resonance technique to achieve port isolations, are developed for V-band direct conversion receivers. A double-balanced resistive mixer, with high input power capability to reduce output power amplification requirements is also developed for millimeter-wave transmitters. A distributed resistive mixer is proposed to achieve wideband performance with low intermodulation. As an alternative to the use of baluns for generating anti-phase signals required in balanced mixers, a balanced oscillator is introduced. This novel oscillator can also operate as a power combining oscillator to obtain higher output power. In addition, a transmission-line stabilising technique can be applied to improve the oscillator phase noise. For the analysis of mixer circuits, the large-signal / small-signal analysis technique is extended to the case of multiple device mixers. For baluns used in the balanced mixers, a simplified analysis is applied, leading to a new class of impedance transforming baluns, which can be matched at all ports. The MMIC mixers, oscillator and baluns are realised using Marconi Caswell Ltd. foundry process. The performances of the fabricated MMICs are verified using on-wafer measurements. Theoretical analyses of the multiple device mixers and baluns are in good agreement with experimental results. The oscillator power combining and frequency stabilising techniques are also demonstrated experimentally.