Thesis (MScEng) -- Stellenbosch University, 2002. / Some digitised pages may appear illegible due to the condition of the original hard copy. / ENGLISH ABSTRACT: Harmonic mixers are capable of extended frequency operation by mixing with a harmonic of the LO (local oscillator) signal, eliminating the need for a high frequency, high power LO. Their output spectra also have certain characteristics that make them ideal for a variety of applications. The operation of the harmonic mixer is investigated, and the mixer is analyzed using an extension of the classic mixer theory. The synthesis of harmonic mixers is also investigated, and a design procedure is proposed for the design and realization of a variety of harmonic mixers. This design procedure is evaluated with the design and realization of two harmonic mixers, one in X-band and the other in S-band. Measurements suggest that the procedure is successful for the specific applications. / AFRIKAANSE OPSOMMING: Harmoniese mengers kan by hoer frekwensies gebruik word as gewone mengers deurdat hulle gebruik maak van ‘n harmoniek van die LO. ‘n Hoe-frekwensie, hoe-drywing LO word dus nie benodig nie. Die mengers se uittreespektra het ook ‘n aantal karakteristieke wat hulle goeie kandidate maak vir ‘n verskeidenheid van toepassings. Die werking van die harmoniese menger word ondersoek deur uit te brei op die klassieke menger-teorie. Die ontwerp van die harmoniese menger word vervolgens ondersoek, waama ‘n ontwerpsprosedure voorgestel word vir die ontwerp van ‘n verskeidenheid van harmoniese mengers. Hierdie prosedure word getoets met die ontwerp en realisering van twee harmoniese mengers, een in X-band en die ander in S-band. Vanuit die metings is dit duidelik dat die ontwerpsprosedure geslaagd is vir die spesifieke geval.