Description
The wireless age poses an unprecedented strain on global spectrum resources. As such,the available frequency spectrum is becoming more segmented, creating a need for wireless front-ends with wide bandwidths and unpaired spectrum capabilities. The features of time-division duplexing (TDD) lend themselves to this current and future need, making it a growing means of wireless communication across the mobile spectrum.
Integrating a high-power transmitter and a highly sensitive receiver on the same antenna, as is desired in TDD, remains a difficult problem for time-division duplexing transceivers. This work describes wide-band TDD solutions which enable the integration of a power amplifier (PA) on the same antenna as a sensitive low-noise amplifier (LNA).
The first part of this work discusses the design of a transmit/receive (Tx/Rx) switch, a solution for transceiver integration, implemented in bulk CMOS. The simulation results from the extracted layout of this design show improved insertion loss performance and power tolerance over the state-of-the-art Tx/Rx switches in CMOS.
The second part of this work presents the design of a second TDD solution, which implements device re-use, a novel approach to the TDD power tolerance problem. This solution overcomes some of the inherent non-idealities of a CMOS Tx/Rx switch, such as insertion loss, by embedding an LNA within the devices of a digital PA. The results from an extracted layout of this device are also presented.
The end result of this work is two different, novel approaches to integrating transmit and receive circuitry on the same antenna, each achieving state-of-the-art performance. We also provide a discussion of the benefits and drawbacks of each solution.