Ultra-­Broadband Communications using Transformer-­Based Poly-­Phase Network

Technology #6975

A differential folded transformer quadrature coupler is used for generating high quality, fully differential signals that have low-­loss, ultra-­broad bandwidth and can be fabricated in a compact package

Background: Different communication systems such as RF (Radio Frequency), mm-­Wave (Millimeter) and Mixed Signal circuits use quadrature signal (I/Q) signals in their operation. Generating these quadrature signals efficiently is a key requirement in the design of these systems. Many of the current designs struggle with passive loss, amplitude/phase balance, bandwidth, and robustness of the quadrature signals generated, which in turn limits system capability and overall performance. These performance issues are related to the use of RC-­CR (R-­Resistive, C-­Capacitive) pairs and poly-­phase extensions for the generation of quadrature signals in current designs. This invention seeks to overcome these and other performance related issues by developing a novel transformer-­based poly-­phase network topology which substantially extends the operational bandwidth while minimizing loss and providing for good amplitude matching.

Technology: Georgia Tech inventors have developed a differential folded transformer quadrature coupler is used for generating high quality, fully differential signals that have low-­loss, ultra-­broad bandwidth and can be fabricated in a compact package. The design has been implemented in a standard 65nm bulk CMOS process and high quality quadrature signals over a decade bandwidth generated. The proof-­of-­concept design of a 3 stage transformer poly-­phase network showed strong performance over a 2-­20 GHz operating range and low values for output phase error, magnitude mismatch and image rejection ratios. In addition to superior performance, this design can be implemented in a significantly reduced chip area allowing for easier on-­chip, fully integrated system implementation. A high degree of design robustness is also achieved in this design by the ability of the poly-­phase network to suppress any common magnitude/phase offset.

Potential Commercial Applications:
 

• Communication and sensor systems  

• Wireless communication systems 

• Radar systems of the phase array or mode-­former types and RF/mm-­wave/sub-­mm-­wave systems for high-­performance radar, phased-­array, imaging, high-­speed communication, and spectroscopy

Benefits:
• Low loss

• Compact design 

• Generates high-­quality fully differential quadrature

• Can be readily extended to high-­order configurations for broadband operation
• High performance 

Researchers:

Hua Wang — Assistant Professor — Georgia Tech School of Electrical and Computer Engineering 

Hua Wang — Associate Professor — Georgia Tech School of Electrical and Computer Engineering

Jongseok Park — Graduate Student — Georgia Tech School of Electrical and Computer Engineering