| IP개요 |
This paper reports a 60 GHz four-element beam-tapering phased-array transmitter with a lower side-lobe level. To reduce the side-lobe level, vector-sum phased shifter (VSPS) with low phase and gain variation and variable gain amplifier with low impedance and phase variation are proposed. The proposed VGA not only has low phase and impedance variations during gain control, but also shows high linearity under low supply voltage. Analysis reveals that proposed VGA reduces gain/phase error in vector modulation. In addition, the transformer-based current-reuse technique is adopted to enhance the gain of the phased array channel while consuming low DC power. With the proposed VSPS and VGA, the proposed 1-channel compensates the gain variance of phase shifters and, simultaneously, excites the non-uniform amplitude to each array element. Implemented in a commercial 28 nm CMOS process, the integrated array chip displays a low RMS gain error and phase error in the frequency range 57–66 GHz, while consuming a low dc power and occupying a small chip area. The fabricated array will be integrated with a 1 × 4 array antenna to verify the beam-forming and beam-tapering operations. With proper gain and phase control, the integrated array decreases the side-lobe level by up to 8.7 dB. |
