1 Introduction

K-band operates from 18 GHz to 40 GHz. The common applications tend to fall in Ku-band from 18 – 20 GHz and a portion of Ka-band from 26 – 28 GHz. A direct conversion architecture supplanted the traditional discrete super-heterodyne architecture for these systems as new high frequency modulators and demodulators arrived on the market.

The direct conversion architecture in itself is not new. The benefits of a streamlined architecture and wide bandwidth capabilities are well documented; however, the application in very high frequencies may introduce complexities. Previously there was not a good alternative, but new RF sampling devices bring back the super-heterodyne architecture to the forefront.