Complementary Current-Mode Biquad Filter for Tunable 5G Bandwidth
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Solution Overview
Problem
Current receiver architectures are insufficient to meet the bandwidth specifications of 5G communication services, particularly in millimeter wave (mmW) applications, due to limited reconfigurability and tuning range of conventional filters.
Innovation Solution
A current-mode biquad filter circuit with tunable transconductance and capacitance is introduced, featuring complementary active filter circuits and a capacitive element, enabling higher bandwidth support up to 1 GHz and improved reconfigurability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional filters are used in receiver architecture, then device complexity is reduced, but bandwidth capability and reconfigurability are insufficient for 5G mmW applications
Solution Approach 1:
The filter circuit employs dynamically controllable transconductance values (gm1, gm2, gm3, gm4) that can be adjusted in real-time to reconfigure the filter characteristics. This dynamic control enables the filter to adapt to different bandwidth requirements and frequency ranges, achieving 5G mmW performance without requiring multiple fixed filters
Solution Approach 2:
The invention changes the operating parameters of the filter by using variable transconductance elements and tunable capacitive values. By modifying these parameters, the filter can operate across wide bandwidths and different frequency bands, resolving the contradiction between maintaining simple circuit topology and achieving high adaptability
2Reliability
If conventional filters with fixed parameters are used, then manufacturing precision requirements are reduced, but process variations and component mismatch cause Q and f0 to vary
Solution Approach 1:
The complementary active filter circuits are designed with feedback mechanisms that compensate for process variations and component mismatches. The feedback loops adjust the transconductance and capacitance values to maintain stable center frequency (f0) and quality factor (Q) despite manufacturing tolerances, thereby improving reliability without requiring ultra-precise component matching
3Measurement precision
If high Q and high f0 filters are designed, then signal processing performance is improved, but the filters become sensitive to process variations and component mismatch
Solution Approach 1:
The filter uses continuously tunable transconductance and capacitance parameters that can be adjusted to optimize the Q and f0 values. This parameter flexibility allows the filter to achieve high signal processing performance while compensating for process variations, making the design more robust without sacrificing filtering quality
Data Source
AI summary
Certain aspects of the present disclosure provide methods and apparatus for processing signals using a current-mode biquad filter, which may have a tunable bias current and/or tunable capacitance. One example apparatus is a current-mode biquad filter circuit that includes a first input current node, a first capacitive element coupled to the first input current node, a first output current node, a first active filter circuit coupled between the first input current node and the first output current node, and a second active filter circuit coupled between the first input current node and the first output current node. The second active filter circuit is complementary to the first active filter circuit.