Design of a Low-Noise 24 GHz Receiver Using

MMICs

Project Background

23.6-24.0 Ghz is a “quiet”

band

Resonant frequencies of water vapor, with 24

GHz marked

Eric Tollefson, Rose-Hulman Institute of TechnologyFaculty Advisor: Dr. L. Wilson Pearson

•Passive band is used for weather prediction using satellites

•Measuring man-made noise in the passive band and surrounding frequencies

•Need very low noise receiver for maximum sensitivity

•Prior design: 7 dB noise figure

•Noise figure is dominated by the first stage amplifier (see equation below)

•New design will replace first amplifier stage to get a lower total noise figure

•Improvement should be about .6 dB over previous design

21

3

1

21

11

GG

F

G

FFFcas

The current receiver front-end, with NF=7 dB @ 24 GHz(by Joel Simoneau)

New amplifier: Fujitsu FMM5701X

•18-28 GHz•13.5 dB gain @ 24 GHz•NF=1.4 dB min @ 24 GHz•Requires external bias and matching circuitry•Difficult to perform out-of-circuit testing

Single-stub tuner

Quarter-wave transformer

Bias Tees

MMIC

New Design

Results

520 μm

450

μm

Future Work•Troubleshoot to obtain correctly working prototype

•Verify that matching design is correct using s-parameters

•Measure amplifier gain and noise figure

•Integrate into complete system, including DC bias circuitry

•Measure whole-system noise figure and gain parameters for comparison with previous design

•Take new noise measurements

Images courtesy of J. Simoneau

Image courtesy of Fujitsu

Image courtesy of J. Simoneau

S-Parameter Measurements of prototype

from 23.6-24.0 GHz (blue) and design

values (green)

Bias Conditions:

VDD=0 V

IDD=0 mA

VGG=-1 V

Bias Conditions:

VDD=5 V

IDD=72 mA

VGG=-1 V