Project Updates


May 9, 2012

Our fabricated antenna system with surface mount resistors arrived.  The plan is to quickly demonstrate two separate antennas that resonate at different frequencies as well as the DC-DC converter.  Two wires will be soldered to connect the patches to simulate a closed MEMS switch.  After graduation, work will be continued to implement MEMS on the antenna system.

April 3, 2012

The final design of the Antenna system (both with and without ground pads for the MEMS) was sent to Micro-Circuits, Inc. for review.  If all goes well, fabrication will begin with a 2-3 week turn around time.

March 29, 2012

Simulations of the Antenna system continued.

March 27, 2012

Members of the RF senior project teams went to Camtek in Bloomington to discuss the soldering of surface mount components for the respective projects.  They may be able to directly solder a wire to the MEMS pads as an alternative to wire bonding.

March 22, 2012

We spent half of the lab period at Endotronics in East Peoria working with the wire bonding machine.  Unfortunately, it was not working correctly so we will have to look for possible alternatives to wire bonding at Endotronics. 

March 8, 2012

In order to reduce manufacturing costs, we are aiming to manufacture 2 types of antenna systems (with floating or no ground planes) and the evaluation boards on one 9"x12" laminate.  The preliminary simulations with inset-feed impedance matching look promising.  We need to reduce the signal strength at 1.7GHz while maintaining a strong 1.227Ghz signal.

March 6, 2012

The Gerber Files of the evaluation board were sent to Micro-Circuits, Inc. for review.  The evaluation board was converted to RO3010 laminate (same as patch antenna) with several different MEMS ground patch orientations.  Mike researched the feasibility of inset-feed impedance matching, which would simply our overall design.

March 1, 2012

The Design Review PowerPoint was uploaded to our website.  Simulations continued.  Emerson coaxial connectors and surface mount (1.6x0.8mm) 100k ohm resistors were ordered from Digi-Key.

February 28, 2012

The Design Review Presentation of the Reconfigurable Antenna was presented to the faculty.

February 27, 2012

Dr. Shastry reviewed our Design Review Presentation and the PowerPoint was finalized.

February 23, 2012

The gap between the MEMS switch and transmission lines was decided to be 0.5mm.  The proposed design of the evaluation board for the MEMS switch was emailed to Bob Modica to be checked over before the board is manufactured.  In Momentum, the S-Parameters of the patch antenna were transferred to an one port network schematic so that the matching network design can begin.

February 21, 2012

In a meeting with Dr. Shastry, the evaluation board design was changed to a smaller size (1.5" x 1.0") with a different square coax connector.  Tuning of the Momentum simulations continued.

February 16, 2012

A preliminary design of the Evaluation Board has been drawn up and started in ADS 2011.  The proposed layout is 2.0" x 1.25" using 50 ohm transmission lines with coax connectors.

February 14, 2012

Momentum simulations continued with the amount of MEMS switches being adjusted.  Also, the design of the evaluation board for the MEMS switch began.  The VT-42 30 mil FR-4 laminate will be used at the suggestion of Bob Modica from Micro-Circuits, Inc.

February 9, 2012

Momentum simulations continued with the 2nd patch.  The 2nd patch length is a lot shorter than expected to get 1.227 GHz as a resonant frequency.  The DC-DC converter issue is caused by the MAX776 IC outputting +15V when it should be +5V.  A different model (MAX774EPA) and new inductors were ordered from Mouser Electronics.

January 31, 2012

In Momentum, switches we added in to connect the 2nd patch but it changed the expected results drastically.  A fix is being worked on currently.  The DC-DC converter issue was narrowed down to the 18R474C inductor or the MAX776 IC.

January 26, 2012

Momentum simulations continued.  The +5V to -90V DC-DC Converter assembly began, but is not currently working.

January 24, 2012

PCAAD 6.0 was used as a quick simulation of our antenna design before transferring to Momentum.  Results were recorded and the design began in Momentum.

January 19, 2012

We finalized our patch lengths and widths from Balani's Equations and PCAAD 6.0 simulations.  A revised tentative schedule for the semester was planned out.

December 6, 2011

In our final lab day, we ordered the parts to our DC-to-DC Converter from Digi-Key and 10 RMSW201 MEMS Switches from RadantMEMS.

December 1, 2011

The Final Project Proposal is posted on our website and to Sakai, which incorporates the changes from Right Hand Circular Polarization to Linear Polarization.  In addition, we continued our research of simulation and the understanding of implementing the RMSW201 MEMS switches.

November 29, 2011

Today we made our final adjustments to our project proposal, as well as continuing simulations in Momentum.

November 22, 2011

Today we continued simulations in Momentum and updated the project website as well.

November 17, 2011

In a meeting with Dr. Shastry, we decided to change from Right Hand Circular Polarization to Linear Polarization due to time constraints.

November 15, 2011

We delivered our Project Proposal Presentation to students and facility

November 10, 2011

In a meeting with Dr. Timpe, we discussed the possibility of doing the wiring bonding to MEMS switches ourselves and the storage of MEMS switches in regards to humidity.

November 3, 2011

Today, we made the decision to attempt to implement RMSW201 MEMS Switches from RadantMEMS as our switching device.  The only issues with these switches are high cost and +/- 90V biasing voltage, which we will deal with through a +5V to -90V DC-DC Converter.

In addition, we also decided on using Rogers Corporation's RO3010 substrate due to its high dielectric constant that will minimize patch sizes.

October 25, 2011

We compiled an excel sheet with comparisons of transistor switches in regards to their package size, insertion loss, isolation loss, and frequency operation range.  The uPG2189TB transistor Switch from California Eastern Labs appears to be the best transistor choice for our application, but we need to compare this switch with pin diodes and MEMS switches.

October 20, 2011

Using PCAAD 6.0, we simulated the preliminary patch antenna calculations and found reasonable VSWR graphs for both 1.575 GHz and 1.227GHz.

October 13, 2011

With the help of the Antenna Design Theory textbook, we calcultaed the preliminary Length and Width measurements of both patch antennas.  Next lab period we will simulate these results.

October 6, 2011

We completed the final version of the Functional Description and Complete System Block Diagram deliverable and submitted it to Sakai.

September 29, 2011

Today we research GPS frequency information from and found what specific resonant frequencies we want for our antenna (1.575 GHz and 1.227 GHz).

September 13, 2011

Where any project has to start, we will have to spend the next 2-4 weeks researching reconfigurable antenna design options and switching methods.