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PhD Preliminary Oral Exam – Manoj Johnson

Frequency/Code-Domain Filtering N-path Filters; A 4-element 28GHz Millimeter-wave MIMO Array with Single-wire Interface

Applying orthogonal sequences to N-path filters promises reconfigurable select/reject filtering of signals based on their spatial, spectral and code-domain properties. Achieving code and frequency-domain notch filtering using inductors instead of capacitors has been challenging due to parasitics and self-resonance associated with large off-chip inductors. In this work, N-path frequency/code-domain reject and select filtering is demonstrated using N-path switching with passive inductors. A cascaded inductor approach and differential N-path filtering is used to overcome inductor parasitics and enable GHz operation. A 65-nm CMOS prototype of a code-domain notch filter followed by a code-domain select receiver demonstrates 0.5GHz to 1.0GHz operation with 26dB blocker filtering with 8dBm power handling, while consuming 60mW (at 1GHz LO) and occupying 1.2mm2 of die area. Millimeter-wave MIMO systems with digitization of every element enable spatial multiplexing, virtual arrays for radar, digital beamforming (DBF) for high mobility scenarios. However, per-element digitization results in a formidable I/O challenge in large-scale tiled MIMO mmWave arrays. This work demonstrates a 28GHz 4-element MIMO RX with a single-wire interface that multiplexes the baseband signals of all elements and the LO reference through code-domain multiplexing. System considerations are presented and the approach is validated through DBF after de-multiplexing of the baseband signals from the single wire. Each element in the array achieves 16dB conversion gain and ∼7dB NF while consuming 60mA from 1.2V. The IC occupies 5.75mm2 in 65-nm CMOS.

Major Advisor: Arun Natarajan
Committee: Un-Ku Moon
Committee: Andreas Weisshaar
Committee: Huaping Liu
GCR: Joseph Louis

Friday, March 13 at 3:00pm to 5:00pm

Kelley Engineering Center, 1005
110 SW Park Terrace, Corvallis, OR 97331

Event Type

Lecture or Presentation

Event Topic


Electrical Engineering and Computer Science
Contact Name

Calvin Hughes

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