Page 24 - SPECTRUM

Shailendra Singh (12EXTPHDE86)

Title of Thesis: Design and Development of Higher Order Sub harmonic

Mixers
ABSTRACT: Microwave mixers are inevitable modules in any RF sub-system.

Enabling frequency translation, mixers have always played a pivotal role for
venturing into the higher frequency domain. Progressive development in

Monolithic Microwave Integrated Circuit (MMIC) technology has enabled the
realization of highly condensed and complex core chip RF modules covering

THz technology via realization of high frequency mixers employing Schottky
diodes. Likewise, the mixing phenomenon has advanced from fundamental

mixing to sub-harmonic mixing wherein higher order of lower frequency Lo-
cal Oscillator (LO) frequency is utilized advantageously making the circuit-

ry compact and avoiding the need for generating higher LO frequencies.

This research work involves investigation wherein three novel findings have
evolved as an outcome of the research; formulating spurious frequency de-

termination, simplifying fundamental I-Q mixer and realizing 6X Sub-harmon-
ic IQ mixer using improved idlers. The findings are briefly described below:

(i) Formulae for Determining Heterodyne System Spurious Frequencies

that Coincide with Desired Output Frequency:

Till date, no direct formulae have been reported for determination of the
lowest order coinciding spurious.

(ii) Proposal and Demonstration of a Simplified Design Topology for I-Q mixers:

Conventional I-Q Mixers utilize hybrids, vias, cross over or wire-bonds for
realization. The proposed design is based on a unique arrangement of

six RF power dividers and avoids complex structures like hybrids or vias.

(iii) Design and Realization of a 6X Sub-harmonic IQ MMIC using Improved
Lumped Component Microwave Multi-Frequency Idler:

Two design methodologies for realization of compact and improved micro-

wave lumped component multi-frequency idlers for monolithic integrated
circuits have been proposed and using this a 6X Sub-harmonic IQ MMIC Mix-

er has been designed.

SPECTRUM Pg. 19 ISSUE 1