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A Phase-Calibration Method for Vector-Sum Phase Shifters Using a Self-Generated LUT
摘要： This paper presents a new self-calibration method for vector-sum phase shifters (PS) to compensate for process variations and achieve reconfigurable operating frequency. The calibration system generates a look-up table for the control voltages of the variable-gain amplifiers of the PS to minimize the rms phase error at a frequency of interest. The calibration system consists of a coupled-line coupler, an amplifier, a power detector (PD), an analog-to-digital converter, and a data processing unit. In this calibration method, first, the amplitudes of IQ vectors are swept and their powers are measured. Then, phase errors are calculated from these power measurements using the cosine formula. Finally, the vector pairs providing the least phase error are chosen for each desired phase shift. The practicality of the proposed system is demonstrated by realizing a self-calibrated X-band 7-b PS fabricated in IHP 0.25-μm SiGe BiCMOS technology, including the on-chip coupler, amplifier, and PD. The calibration system improves the rms phase error by at least 1°, does not degrade the rms gain error, and increases the insertion loss by 1.6 dB. The self-calibrated PS achieves a 2° rms phase error across X-band frequencies. The overall chip size is 2.6 mm2. The power consumption of the PS and the overall system are 110 and 233 mW, respectively. This built-in calibration system mitigates process variation effects, and the performance of the PS can be optimized for any center frequency across X-band.
关键词： BiCMOS,vector-sum phase shifter,look-up table,Self-calibration,process compensation,phase shifter,SiGe
更新于2025-09-23 15:23:52
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A 28-GHz Low-Power Vector-Sum Phase Shifter Using Biphase Modulator and Current Reused Technique
摘要： In this letter, we present a low-power vector-sum phase shifter for upcoming 5G communication at 28 GHz. The ±I/±Q signals for phase synthesis by vector adder (VA) are generated by a 90° coupler and two re?ection-type biphase modulators. Modulators are only biased at 0 and 1.8 V to avoid large insertion loss near their phase reversal region. Our proposed single-ended two branches quadrature structure can avoid the differential variable gain ampli?er and achieve low power and compact area. In addition, we use the current reused technique to connect VA and output buffer to save dc power and suppress a change in output impedance among different phase states. The measured average peak gain is ?3.75 dB at 29.25 GHz. Across all phase states, the measured IP1 dB is better than 5 dBm. The 3-dB bandwidth of S21 is 27–33 GHz. Input and output return losses are also better than 10 dB at this frequency range. Total dc power consumption is only 6.6 mW for 1.8 V supplied voltage. To the best of our best knowledge, this phase shifter has low dc power and compact area at K-band and Ka-band.
关键词： vector adder (VA),phase-invertible variable attenuators (PIVAs),Biphase modulator (BM),current reused technique,vector-sum phase shifter (VSPS),buffer ampli?er (BA)
更新于2025-09-23 15:21:01