Authors | Abolfazl Bijari,Mohammad Amin Mallaki |
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Journal | Journal of Electrical and Computer Engineering Innovations |
Page number | 1-10 |
Serial number | 1 |
Volume number | 10 |
Paper Type | Full Paper |
Published At | 2023 |
Journal Type | Typographic |
Journal Country | Iran, Islamic Republic Of |
Journal Index | isc |
Abstract
Background and Objectives: In wireless communications, receivers play an essential role. Among receiver architectures, the direct-conversion receiver (DCR) architecture has been selected due to its high level of integration and low cost. However, it suffers from DC offset due to self-mixing, I/Q imbalance, and flicker noise. Methods: This paper presents a new LNA-mixer with variable conversion gain (VG-LM) for wireless local area network (WLAN) applications. A low noise transconductance amplifier (LNTA) is used as the transconductance stage in the Gilbert cell mixer. The wide variable conversion gain range is achieved by the change in LNTA’s transconductance and transconductance of the mixer switching transistors. Results: The proposed LNA-mixer is designed and simulated using 0.18µm CMOS technology in Cadence Spectre RF. The post-layout simulations exhibit the proposed circuit operates at 2.4 GHz with a bandwidth of 10 MHz. In addition, the conversion gain is changed from -3.9 dB to 23.9 dB with the variation of the controlled DC voltage from 0.5 to 1.8. At the high gain, the double-sideband noise figure (DSB-NF) is less than 3.7 dB, and its third-order intermodulation point (IIP3) is -9 dBm. The power consumption is 22 mW from the supply voltage of 1.8 V. The circuit occupies 743 µm×775 µm of core chip area. Conclusion: Using the proposed circuit, the RF front end receiver does not need the low noise amplifier (LNA) and variable gain amplifier (VGA).
tags: Variable Conversion Gain, Low Noise Transconductance Amplifier (LNTA), Active mixer, Noise Figure