SPACE AND NAVAL WARFARE SYSTEMS
Antenna and Laser Utilization in the US Navy
Collecting dish containing methanol
GRANT # 0653277
Gabriela Banks ◊ Southwestern College ◊ Majoring in Mechanical Engineering ◊ [email protected]
Sergio Montoya ◊ Southwestern College ◊ Majoring in Physics ◊ [email protected]
Sean Mott ◊ Southwestern College ◊ Majoring in Electrical Engineering ◊ [email protected]
Ayax Ramirez ◊ Head of Advanced Technology Branch ◊P. Mike McGinnis◊ Technical Specialist ◊Ryan P. Lu ◊ Project Engineer
- The initial setup for the fabrication of microspheres was designed to determine if micro and nano-sized particles could in fact be created.
- The main concern was the collection of particles ejected within the plasma plume produced through the ablation of the silicon wafer.
- The network analyzer was also used to do testing on the Mast Clamp Current Probe (MCCP). The MCCP allows for multiple frequency spectrums to be transmitted via the same antenna by inducing a current through the metal carrier.
- Currently, the Navy must use different antenna lengths if they are transmitting over different frequency ranges. The MCCP provides a way for the Navy to reduce the amount of antennas that are required to be on ships.
- The smith chart to the left is one of the desired results that the network analyzer can produce.
- It shows an accurate picture of how the antenna being tested reacts in response to different frequencies. The red line in the center of the chart represents the antenna.
- Space and Naval Warfare Systems San Diego (SPAWAR) is the US Navy’s research, development, test and evaluation, engineering, and fleet support center for command, control and communication systems.
- As student interns at SPAWAR, we worked under the Advanced Technology Branch, with individual experiences at the antenna model range and the laser test facility. Some of our roles included testing and evaluation of antennas, modeling of antenna characteristics on 1/48 scale brass naval ships, and testing, modeling, and fabrication of silicon microspheres through the laser ablation process.
- Most of the personnel that we interacted with were physicists and electrical engineers, ranging from permanent SPAWAR employees to professionals doing summer research. We also had the opportunity to supervise high school interns in their research projects.
- The network analyzer was used to compare a traditional antenna to one utilizing multiple current probes as shown on the left. This was done to ensure that the MCCP was capable of the same performance as a traditional antenna over the desired frequency spectrum.
- The majority of the antennas that we tested at the antenna range fell well within the desired VSWR ratio.
- The experiments measuring the MCCP showed that it had almost the same characteristics over multiple frequency ranges as its traditional counterparts.
Laser beam hitting silicon wafer
- The final setup for the experiment was done by lowering the collecting dish and forcing the particles that were ejected to fall through the laser. With enough laser energy and a high pulse rate, we were hoping the particles would be hit enough times to generate nano-particles that were spherically uniform.
1/48 scale brass ships are placed on a roundtable underneath the white pillars. As they rotate around, an antenna is moved up and down one of the pillars, transmitting a signal as it moves, testing the capabilities of the antennas mounted on the ship.
Mast Clamp Current Probe antenna
- Through our experiences during this internship at SPAWAR, we were able to get a better idea of how engineering teams work together towards a accomplishing a common goal. Our mentors not only provided guidance through the engineering aspects of their work, but also provided insight on what to expect as future engineers in industry.
- It was rewarding to assist in developing a product based on the needs of the customer. In our case, the customer was the Navy and the systems we assisted in developing will help to ensure that the U.S .Military is the forerunner in scientific technology.
- During testing at the antenna site, the primary piece of test equipment used was the network analyzer.
- The initial setup for the fabrication of silicon microspheres generated enough micro-particles, though amorphous in shape, that encouraged further experimentation in seeking spherically uniform nano-particles.
Antenna model range
- For Silicon Microsphere Fabrication experiments, we first had to understand the theory and physics of the Excimer laser. Also, we had to learn about the theories of laser annealing and laser ablation.
- After understanding the theory behind lasers, we were able to operate the laser systems and X-Y translation stages and perform experiments that generated micro and nano-sized particles through the laser ablation process.
Silicon micro-particles seen through an optical microscope with x200 magnification.
Network analyzer screen
- By forcing ejected particles to fall through the laser beam, we were able to obtain smaller particles and also some spherical silicon fragments, like the one seen here through a scanning electron microscope (SEM)
- Pictured above is the network analyzer and a picture of its screen while measuring an antenna. The main measurements that we did had to do with the impedance and the Voltage Standing Wave Ratio (VSWR) of the antenna at different frequencies.
- VSWR represents power that is reflected back towards the transmitter when it is sent out of the antenna. A lower VSWR means a more suitable antenna for the specified frequency under test.
- Ayax D. Ramirez, Head of Advanced Technology Branch
- Dr. Ryan Lu
- Dr. Andy Henning
- P. Mike McGinnis
- Thank you for all you support, patience, knowledge and for sharing this great experience with us!
Silicon nano-sphere seen through a SEM
with x130k magnification