A 240-GHz VMPS With 1.2° and 0.35-dB RMS Errors in 130-nm BiCMOS:C Technology

This work presents a low phase error (PE) and amplitude error (AE) vector modulator phase shifter (VMPS) in the
$J$
-band. The influence of the IQ crosstalk RF impairment on the performance is analyzed for different vector summation implementations, guiding to the VMPS architecture choice and design optimization. The chosen architecture consists of an IQ analog-controlled voltage-gain amplifier (IQ-VGA), Branchline coupler, and a Wilkinson combiner. Test structures for the variable-gain amplifier (VGA) and the VMPS are manufactured and measured in a 130-nm BiCMOS technology (
$f _{T}/f _{\textbf {max}}$
= 300/500 GHz). For the phase resolution of 11.25°, the VMPS achieves an average rms PE and AE of 1.2° and 0.35 dB, respectively, with equivalent to 5.5 -bits control voltage across the frequency band 220–260 GHz. The VMPS consumes 60 mW from 2.5-V supply and occupies 0.2 mm2 of silicon area. This work presents the least PE and AE across a wide bandwidth for VMPS in silicon technologies above 200 GHz, which is crucial for large-scale beam-steering arrays.