Integrated radio frequency circuits for wideband receivers

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Mikko Kaltiokallio Name of the doctoral dissertation Integrated radio frequency circuits for wideband receivers Publisher School of Electrical Engineering Unit Department of Microand Nanosciences Series Aalto University publication series DOCTORAL DISSERTATIONS 36/2014 Field of research Electronic Circuit Design Manuscript submitted 14 November 2013 Date of the defence 9 May 2014 Permission to publish granted (date) 3 March 2014 Language English Monograph Article dissertation (summary + original articles) Abstract The multisystem, multiband problem in mobile terminals drives up the cost and complexity of the radios by requiring separate dedicated signal paths with discrete filtering. By removing the filters, the radios could be made more cost-efficient and flexible, and the signal path design would be simplified. However, in receivers, this demands that the front-end is capable of withstanding an extremely harsh interference environment while providing good sensitivity. This thesis concentrates on improving and developing receiver circuits that provide a wide reception bandwidth and tolerance against blockers. Wideband receiver circuits are an attractive option to implement the future resource sharing radios with less dedicated hardware. A wideband dual-loop feedback LNA implemented in this work enables simultaneous matching and flat gain response over a 1.6 GHz reception band while only requiring a single inductor in the shunt-peeked load of the LNA. The use of a wideband LNA in a 60 GHz receiver has also been demonstrated. Additionally, wideband buffering circuits are reviewed and compared in this thesis. The fast switching speed of the CMOS technology acts as the key enabler for the research performed in this work. One structure that utilizes this property is the N-path filter, which has been extensively utilized in the circuits presented. A feedback N-path filter in a wideband 2-to6-GHz LNA has been implemented and analyzed. The analysis provides the evaluation of different design trade-offs and a guide to design such a system. Another circuit to use the Npath filter is the 0.7-to-2.7-GHz mixer-first receiver that was implemented together with a wideband CCE antenna. The work highlights the key challenges when wideband interfaces are implemented and suggests a solution to circumvent part of the challenges. The integrated circuit includes low-noise and low-distortion baseband stages to provide good overall performance. Additionally, the circuit demonstrates a novel duty-cycle control circuit for tuning the mixer-first receiver performance. This thesis also includes an analysis and implementation of an active polyphase filter for LO quadrature generation. The analysis provides means for designing stable two-stage APPFs with optimal gain, image rejection ratio and bandwidth while being stable. This is demonstrated in a 1-to-5-GHz APPF that was implementedThe multisystem, multiband problem in mobile terminals drives up the cost and complexity of the radios by requiring separate dedicated signal paths with discrete filtering. By removing the filters, the radios could be made more cost-efficient and flexible, and the signal path design would be simplified. However, in receivers, this demands that the front-end is capable of withstanding an extremely harsh interference environment while providing good sensitivity. This thesis concentrates on improving and developing receiver circuits that provide a wide reception bandwidth and tolerance against blockers. Wideband receiver circuits are an attractive option to implement the future resource sharing radios with less dedicated hardware. A wideband dual-loop feedback LNA implemented in this work enables simultaneous matching and flat gain response over a 1.6 GHz reception band while only requiring a single inductor in the shunt-peeked load of the LNA. The use of a wideband LNA in a 60 GHz receiver has also been demonstrated. Additionally, wideband buffering circuits are reviewed and compared in this thesis. The fast switching speed of the CMOS technology acts as the key enabler for the research performed in this work. One structure that utilizes this property is the N-path filter, which has been extensively utilized in the circuits presented. A feedback N-path filter in a wideband 2-to6-GHz LNA has been implemented and analyzed. The analysis provides the evaluation of different design trade-offs and a guide to design such a system. Another circuit to use the Npath filter is the 0.7-to-2.7-GHz mixer-first receiver that was implemented together with a wideband CCE antenna. The work highlights the key challenges when wideband interfaces are implemented and suggests a solution to circumvent part of the challenges. The integrated circuit includes low-noise and low-distortion baseband stages to provide good overall performance. Additionally, the circuit demonstrates a novel duty-cycle control circuit for tuning the mixer-first receiver performance. This thesis also includes an analysis and implementation of an active polyphase filter for LO quadrature generation. The analysis provides means for designing stable two-stage APPFs with optimal gain, image rejection ratio and bandwidth while being stable. This is demonstrated in a 1-to-5-GHz APPF that was implemented