LNA Progress Report

WEEK 1: September 17 2002
The project was decided to be the SDARS Integrated Front-end Reciver. Group members: Carlos Anaya, Nitin Malhotra and Kara Bendix. We worked on the informative memo.
 
WEEK 2: September 24 2002
We worked on the functional description of the SDARS IFR project.
 
WEEK 3: October 29 2002
I read the the report of the work that was done for this project by the group of 2000. We worked on a system block diagram. I got some parameters from the previous work documentation. SIRIUS Radio is allocated in the bandwidth of 2.32-2.3325GHz.

WEEK 4: November 5 2002
We split the work for this project. Nitin Malhotra Antenna, Carlos Anaya LNA Kara Bendix Down Converter. We discusses integration. We want to have a compacted piece where the antenna, LNA and Down Converter are in one unit. I read some documents on Satellite reception. LNA Noise Figure .6 dB typical .9 dB Max LNA Gain 39.5 to 49 dB.

WEEK 5: November 12 2002
I read on Amplifier desing on the Guillermo Gonzalez book. I went through the Amplifier datasheet MGA 71543 used in previous design.

WEEK 6: November 19 2002
We went to get information on the commercial unit since the department is going to purchase one so we can make test on it and verify the parameters from the previous design. I worked on the stability circles for the transistors.

WEEK 7: November 26 2002
I analyzed the datasheet from the TRK-SR20S TERK antenna. Low noise figure .7dB max and 28.5 - 32.5dB for total active LNA gain. We will consider this specifications for our design.

WEEK 8: December 3 2002
I researched on other kind of transistors that will give the new specifications. I did not found better transistors.

WEEK 9: December 10 2002
We did our first presentation for our project.

WEEK 10: January 28 2003
We set up he commertial unit that we bought and tested it. We received a the test signal and listen to it. We also saw it in the spectrum analizer. We also tested the previous antenna with two lab amplifiers.

WEEK 11: February 4 2003
WE got measurements for the the setup of of the old antenna and the two lab amplifers. Amplifers provided a 40dB gain and with cables the noise figure came about to be 1.5dB. I will use this two parameters to be the maximum values that i can have in my design. And got readings for return losses too. We also got measurements from the signals at different frequencies.

WEEK 12: February 11 2003
We discussed on the overall project work. I researched on the transistor and its properties. s-parameters, bias point.

WEEK 13: February 18 2003
I determined the bias point Vds= 2.4V and Id = 10mA and got the s-parameters for that. I started some preliminary work on the how to design for the first stage low noise figure.

WEEK 14: February 25 2003
Two parts identified. 1st stage low noise amplifer 2nd stage gain possibly a 3rd stage also for gain. We discussed integration. I got preliminary work on stabily circles for the MGA 71523 transistor.

WEEK 15: March 4 2003
I iterated using ADS to get the s-parameters for the center frequency 2.326GHz of the SIRIUS signal. Got stability circles and got a design point for matching networks. I designed input and matching networks for the 1st stage.

WEEK 16: March 11 2003
I simulated the 1st stage with matching networks and such. I got a gain of 16 dB and a noise figure of .78dB which is good since is going to control the overall LNA noise figure. I researched on the bias and choke networks needed to get the apropriate bias and the right RF signal pathway.

WEEK 17: March 25 2003
I designed the following stages for gain 17.49dB for one stage. I designed for mathing networks and got the desired response gain. Unfortunatelly the reflection coefficent S11 in the s-parameters was high. This is important since the lower the better match to the input impedance and there is no changes for possible gain losses. The output matching was good. I had to go back and make sure that the VSWRin was as close as possible to 1. The closer i could get was 8.61 which i traded in for gain now the gain is only 15.8 but S11 is still high -1dB it should be at least lower that -10dB to be considered a good match. I proceded and designed matching networks for that.