A Lange Coupler is a microwave device invented in 1969 by Dr. Julius Lange. It is widely used as power combiner or splitter in many microwave applications. The device works by promoting electromagnetic coupling between closely spaced microstrip transmission lines. The widths of the lines and gaps of the Coupler devices will determine the amount of energy transferred within the device and length of the lines determines the operating frequencies. In a typical modern Lange Coupler design the lines will be designed at .0008” (20 microns) and the gaps between the lines at .0006” (15 microns).
In order for the device to function, there must be interconnections between the various lines at the center and ends of the Coupler. These interconnects are typically called “cross-overs”. Wire bonds are commonly used to make the interconnects but wire bonds have 2 consistent problems:
1) The parasitic effects of different shaped wire bonds makes tuning and stable performance difficult
2) High frequency Lange Couplers with .0008” wide lines are difficult to wire bond to
The UltraBridge process replaces wire bonds by fabricating the interconnects with a repeatable, reliable 3 layer sandwich construction:
Layer 1 – Ultra-thin patterned thin film features provide the interconnections as “cross-unders” not “cross-overs”
Layer 2 – Silicon Nitride is deposited and patterned using in-house deposition equipment to provide a hard, robust, reliable dielectric layer
Layer 3 – Regular thin film circuitry is deposited and patterned as the top layer
The UltraBridge has been used in many defense or military applications and is always finding new customers looking for increased performance or reliability in their new designs. The technique becomes very cost competitive when you need hundreds or thousands of devices. So, if you have a new Lange Coupler design and you need to improve its performance then give us a call – we may be able to help you!
As an industry leader in delivering thin film manufacturing solutions, UltraSource, Inc. is the logical choice as your supplier for build to print thin film circuits and interconnects. We offer a vast array of breakthrough processes and integrated features that can solve many performance, cost, and assembly challenges. UltraSource, Inc. is ISO 9001 certified and registered as a defense contractor with the United States Department of State, Office of Defense Trade Controls and Compliance.