Highly Accurate Frequency Quadrupler Based LO Phase Shifter Achieving 0.29° RMS Phase Error for Wideband E-band Beamforming Receiver

Despite several advantages in terms of linearity and operating bandwidth, LO phase-shifting is not widely used in beamforming transceivers due to the difficulty in realizing fine phase resolution. Regarding the use of a $\times \mathrm{M}$ frequency multiplier, the phase resolution at $\mathrm{f}_{\text{LO}}/\mathrm{M}$ should be much higher than that desired at $\mathrm{f}_{\text{LO}}$ Here, we propose a frequency multiplier based LO phase-shifting technique that does not reduce the phase resolution after the frequency multiplication. At the cost of a few phase states out of $2^{\mathrm{n}}$, the phase resolution at fLO/M can be retained after the frequency multiplier. For experimental evaluation, the proposed scheme was implemented in an E-band beamforming receiver. Because the proposed scheme is suitable for fine resolution and broadband transceivers at millimeter-wave frequencies, the bandwidth of the receiver reaches as high as 23 GHz at 77 GHz with phase resolution and rms phase error of 2.835° and 0.29°, respectively.