ENGR 1202-EE1 Project:

Bluetooth Antenna Fabrication

in the Clean Room

Team 4: Collin Black, Tyler Martin, Dalton Vance

Problem Statement:

• Conduct Research required to design and fabricate an antenna

• The max size is 20mm by 20mm and the minimum size is 10mm by 1omm

• No shape corners

• Determine the best conductor

• The antenna can be Bluetooth, Wi-Fi, RFID, or GPS

Research of Bluetooth

• Bluetooth uses radio waves instead of wires or cables

• They are only capable of short range (10m) and operate at 2.45 gigahertz.

• Bluetooth devices consume a small amount of energy, many devices can run off of very small battery's for months.

https://www.asus.com/us/Networking/USBBT400/

Research of RFID

• Radio Frequency Identification is the use of radio waves to read information stored on a tag.

• There are two types of RFID passive and battery powered.

• Passive- uses interrogator’s radio wave energy to send information back to the interrogator.

• Battery powered- uses a small battery to relay the information.

• RFID can use a frequency of 125KHz, 13.56 MHz or 860 to 930 MHz. http://www.epc-rfid.info/rfid

Research of Wi-fi

• Wi-fi stands for wireless fidelity

• Wi-fi uses a network of radio waves to transmit information

• Wi-fi needs a larger system of devices including a computer, router and servers

• The frequency used is 2.45 gigahertz

http://computer.howstuffworks.com/wireless-network.htm

Research of GPS

• GPS stands for Global Positioning system.

• GPS works by connecting to 3 or 4 of the nearest satellites in orbit. The satellites then transmit the information to a receiver on earth.

• The frequency of a GPS signal is 1572 MHz or 1227 Mhz. https://balkam.wordpress.com/category/gps/

Our Choice

As a team we decided to use a quarter wavelength, aluminum Bluetooth antenna.

• We used quarter wavelength to make the antenna smaller and cheaper.

• We chose aluminum because it was the cheapest, offered good conductivity, and easy manufacturing.

https://www.klgadgetguy.com/tag/bluetooth/

Antenna Length Calculations

𝐁𝐥𝐮𝐞𝐭𝐨𝐨𝐭𝐡 𝐑𝐚𝐧𝐠𝐞:𝟐𝟒𝟎𝟎−𝟐𝟒𝟗𝟕 𝐌𝐇𝐳

𝐌𝐢𝐝𝐩𝐨𝐢𝐧𝐭 = 𝟐𝟒𝟗𝟕−𝟐𝟒𝟎𝟎

𝟐= 𝟐𝟒𝟒𝟖.𝟓 𝐌𝐇𝐳

𝐓𝐨𝐭𝐚𝐥 𝐖𝐚𝐯𝐞𝐥𝐞𝐧𝐠𝐭𝐡: 𝛌 = 𝐜

𝐟=

𝟐.𝟗𝟗𝟕𝟗𝟐𝟔 ∗ (𝟏𝟎𝟖)

𝟐. 𝟒𝟒𝟖𝟓∗ 𝟏𝟎𝟗 = . 𝟏𝟐𝟐𝟒𝟑𝟗𝟏𝟒𝐦 𝐨𝐫 𝟏𝟐𝟐.𝟒𝟒𝐦𝐦

𝐐𝐮𝐚𝐭𝐞𝐫 𝐖𝐚𝐯𝐞𝐥𝐞𝐧𝐠𝐭𝐡: 𝟏

𝟒𝛌=

𝟏𝟐𝟐.𝟒𝟒𝐦𝐦

𝟒= 𝟑𝟎.𝟔𝟏𝟎𝐦𝐦

𝐅𝐢𝐧𝐚𝐥 𝐀𝐧𝐭𝐞𝐧𝐧𝐚 𝐋𝐞𝐧𝐠𝐭𝐡:𝟑𝟎.𝟔𝟏𝟎𝐦𝐦

Safety in the Clean Room

• Each team member had to complete the clean room safety test before we could enter the clean room.

• We had to wear clean room garments to avoid contaminating the air.

• Gloves and goggles were required to be used when working with acids.

This image shows the safety gloves, safety goggles and clean room garments

Dimension DrawingQuarter Wavelength for 2448.5MHz

Antenna Length is 30.61mm

Auto-Cad dimension drawing

Decision Matrix

We choose Aluminum as our conductor

Our strongest points:

• Cost

• Conductivity

The Mask

• The Mask was designed in Aut0CAD for the photolithography process.

• Each square was made to be 16mm by 16mm

• The design was printed onto clear plastic by an inkjet printer.

The Mask

Above: Cutting out the Mask

Photolithography

Photoresist was applied and it was spun a 4k rpm. Then the wafer was soft baked for 1 minute on a hot plate. Next the wafer was placed on the UV lamp with the mask for one minute to remove the photoresist outside of our mask lines. Last the remaining photoresist was developed and rinsed.

Appling photoresist to the wafer

Above: Placing the wafer and mask on the UV lampBelow: Developing the exposed photoresist

Conductor Etching• The antenna wafers were dipped into an acid to etch away the aluminum not

protected by the photoresist. • After etching the wafers were placed in DI water for cleaning.

Placing the wafer in aluminum etch Etching away the unprotected aluminum Placing the etched wafers in deionized water

Dicing and Final Product

• The last step of the process was to cut the individual antenna out of the wafer.

• To do this, we used an automated diamond saw to slice along the box lines from our design.

A single antenna with a dime for scalehttp://www.4semi.com/mAllItems.cfm?menuid=m_6_4

The dicing saw

Big Picture Issues

• The internet of things

• Bluetooth devices could be used to connect devices all through a house. There low power consumption is ideal for devices that will be on extended periods of time.

https://www.utest.com/articles/testing-for-security-with-the-internet-of-things

Possible Improvements

• Reduce the size of a single antenna to fit more on a wafer, this will lower cost and make the process more efficient.

• With an improved mask, the photoresist process would leave clean and unbroken lines allowing for better connectivity.

http://www.elveflow.com/microfluidic-tutorials/soft-lithography-reviews-and-tutorials/introduction-in-soft-lithography/soft-lithography-definitions/

Conclusion• We were able to create a Bluetooth antenna for around $1 each.

• The demand for Bluetooth devices is steadily increasing.

• Bluetooth antennas are the cheapest solution for short distance transmissions.

• Their low power usage makes them ideal for cheap consumer products.

http://paidsocialmediajobs.com/pages/join/?hop=galus&vtid=

http://www.memecenter.com/fun/11838/dilbert-if-we-had-money

Statement of Original Work

As a team, we certify that all work presented is our original work.

Refrences

• "How it works | Bluetooth Technology Website." Bluetooth. Accessed March 14, 2017. https://www.bluetooth.com/what-is-bluetooth-technology/how-it-works.

• "What is RFID?" EPC-RFID. Accessed March 14, 2017. http://www.epc-rfid.info/rfid.

• "What is WiFi and How Does it Work?" CCM. Accessed March 14, 2017. http://ccm.net/faq/298-what-is-wifi-and-how-does-it-work.

• "How GPS Works." How GPS Works. Accessed March 14, 2017. https://www.maptoaster.com/maptoaster-topo-nz/articles/how-gps-works/how-gps-works.html.