A 2.0 GHz IQ Imbalance Compensator With Programmable Switch Biases in a Passive Mixer

Zhang, Weifeng; He, Hongyin; Wang, Riyan

doi:10.1109/tcsii.2018.2799571

Cited by 5 publications

(4 citation statements)

References 13 publications

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“…However, due to the rather complex circuit structure, it introduces large parasitic elements and thus the tuning range is very limited. Thus, this technique is found to be not as effective in mm-wave band as in the sub-6 GHz [5,[22][23][24] either.…”

Section: Lo Generation Path and Phase Mismatch Calibrationmentioning

confidence: 94%

28-GHz CMOS Direct-Conversion RF Transmitter with Precise and Wide-Range Mismatch Calibration Techniques

2022

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A millimeter-wave direct-conversion radio-frequency (RF) transmitter requires precise in-/quadrature-phase (I/Q) mismatch calibration and dc offset cancellation to minimize image rejection ratio (IRR) and LO feedthrough (LOFT) for ensuring satisfactory output spectral purity. We present a 28-GHz CMOS RF transmitter with an improved calibration technique for fifth generation (5G) wireless communication applications. The RF transmitter comprises a baseband amplifier, quadrature up-conversion mixer, power amplifier driver, and quadrature LO generator. The I/Q amplitude mismatch is calibrated by tuning the gate biases of the switching stage FETs of the mixer, the I/Q phase mismatch is calibrated by tuning the varactor capacitances at the LC load of LO buffer, and the dc offset is cancelled by tuning the body voltages of the differential-pair FETs at the baseband amplifier. The proposed technique provides precise calibration accuracy by employing mV-resolution tuning voltage generation via 6-bit voltage digital-to-analog converters. It also covers wide calibration range while minimizing the impact on the circuit’s bias point and dissipated current during calibration. Implemented in a 65 nm CMOS process, the RF transmitter integrated circuit shows output-referred 1 dB compression power of +6.5 dBm, saturated output power of +12.6 dBm, and an operating band of 27.5–29.3 GHz while demonstrating satisfactory performances of −55.9 dBc of IRR and −36.8 dBc of LOFT.

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Section: Lo Generation Path and Phase Mismatch Calibrationmentioning

confidence: 94%

28-GHz CMOS Direct-Conversion RF Transmitter with Precise and Wide-Range Mismatch Calibration Techniques

2022

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“…However, these kinds of schemes require a large area and high power dissipation. Furthermore, some improved analog solutions were suggested later, such as the local oscillator (LO) I/Q imbalance cancellation circuits [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

A Hybrid Scheme for TX I/Q Imbalance Self-Calibration in a Direct-Conversion Transceiver

Wang,

Gao,

Liu

et al. 2024

Electronics

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A generic transmitter (TX) I/Q imbalance self-calibration method, which was designed based on a hybrid analog and digital structure, is proposed in this paper. The whole calibration scheme was implemented using low-complexity digital–analog circuits based on a zero-force feedback loop. In order to eliminate the negative effect of local oscillator (LO) harmonics on the calibration, we used a variable-delay line (VDL) in the analog domain instead of the digital phase compensator. The prototype chip was fabricated within a 0.2∼5.0 GHz direct-conversion transmitter in a 65 nm CMOS process, and measurements found an image rejection ratio (IRR) of 65 dBc.

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“…Hardware implementation of the DPD and IQ imbalance compensation models is nowadays common practice in every modern mobile base station. However, the problem of PA's nonlinearity is not the only concern in the transmission, there exists other issues like up‐conversion and down‐conversion at mixing, which introduce unwanted distortions occurring at the in‐phase/quadrature (IQ) modulation/demodulation process that also contribute to the undesired effects caused by the

I false(t false)

and

Q false(t false)

imbalance . On the one hand, a linearization approach with feedback predistortion (PD) technique has been introduced in Belabad et al, which describes a model for a full MPM PD system employing 16‐QAM, but the system was just simulated in M ATLAB ‐Simulink.…”

Section: Introductionmentioning

confidence: 99%

“…However, the problem of PA's nonlinearity is not the only concern in the transmission, there exists other issues like up-conversion and down-conversion at mixing, which introduce unwanted distortions occurring at the in-phase/quadrature (IQ) modulation/demodulation process that also contribute to the undesired effects caused by the I(t) and Q(t) imbalance. [11][12][13][14][15] On the one hand, a linearization approach with feedback predistortion (PD) technique has been introduced in Belabad et al, 16 which describes a model for a full MPM PD system employing 16-QAM, but the system was just simulated in MATLAB-Simulink. On the other hand, a PD model implemented into a field-programmable gate array (FPGA) consisting of frequency-selective for PA linearization was introduced in Cárdenas-Valdez et al 17 Gilabert et al 18 and Jaraut et al 19 proposed an effective multiband PA linearization by DPD implemented into digital signal processing FPGA-DSP boards.…”

mentioning

confidence: 99%

FPGA‐based system for effective IQ imbalance mitigation of RF power amplifiers

Pérez¹,

Cazares²,

Galaviz-Aguilar

et al. 2020

Circuit Theory & Apps

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Summary To provide an adequate signal integrity to a power amplifier (PA), we propose a digital system for the degradation at the transmitter path, and it is implemented on a field‐programmable gate array (FPGA) board. The proposed system offers the following features: A M‐ary quadrature amplitude modulation (QAM) digital signal generation and in‐phase/quadrature (IQ) imbalance mitigation, and by default, it performs as a predistortion model extraction from PA‐measured data. The simulations and tests provided are performed to effectively verify the PA linearity by using 256‐QAM signals. The nonlinearities are predicted as a reliable solution for linearizing the PA from measurements of AM/AM and AM/PM conversion curves. The performance is evaluated in terms of linearity, computation complexity, and FPGA hardware synthesis according to a dependability compliance of digital signal processing. Finally, the model is validated with input/output data observations to linearize the model with a fitting normalized mean squared error (NMSE) of around −35 dB, a spurious free dynamic range of 40 dBm, and an adjacent channel power ratio reduction by −20 dBm, for a class‐AB broadband radio frequency PA GaN HEMT of 10 W working at 2.34 GHz.

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A 2.0 GHz IQ Imbalance Compensator With Programmable Switch Biases in a Passive Mixer

Cited by 5 publications

References 13 publications

28-GHz CMOS Direct-Conversion RF Transmitter with Precise and Wide-Range Mismatch Calibration Techniques

28-GHz CMOS Direct-Conversion RF Transmitter with Precise and Wide-Range Mismatch Calibration Techniques

A Hybrid Scheme for TX I/Q Imbalance Self-Calibration in a Direct-Conversion Transceiver

FPGA‐based system for effective IQ imbalance mitigation of RF power amplifiers

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