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A probe station based setup for on-wafer antenna measurements is presented. The setup allows for measurement of return loss and radiation patterns of an on-wafer antenna--henceforth referred to as the antenna under test (AUT), radiating at broadside and fed through a coplanar waveguide (CPW). It eliminates the need for wafer dicing and custom-built test fixtures with coaxial connectors or waveguide flanges by contacting the AUT with a coplanar microwave probe. In addition, the AUT is probed exactly where it will be connected to a transceiver IC later on, obviating de-embedding of the measured data. Sources of measurement errors are related to calibration, insufficient dynamic range, misalignment, forward scattering from nearby objects, and vibrations. The performance of the setup is demonstrated from 2 to 40 GHz through measurement of an on-wafer electrically small slot antenna ([[lambda].sub.o]/35 x [[lambda].sub.o]/35, 3.5 x 3.5 [mm.sup.2]) radiating at 2.45 GHz and an aperture coupled microstrip antenna (2.4 x 1.7 [mm.sup.2]) radiating at 38 GHz. Index Terms--Aperture coupled microstrip antenna, electrically short antenna, on-wafer antenna measurements, probe station.

A device architecture for improving the linearity of barium-strontium-titanate (BST) capacitors is proposed, analyzed, and experimentally demonstrated. The basic concept is to reduce the RF swing across the ferroelectric varactors by connecting multiple capacitors in series. With proper biasing networks, the overall device preserves its tunability. In this paper, the proposed architecture is analyzed to derive the equations that relate its quality factor and tuning speed to the design parameters. Parallel-plate BST capacitors are fabricated based on the architecture. Various measurements are performed to demonstrate the efficacy of the technique. The third-order intercept point at input ([IIP.sub.3]) is found to be improved by 16 dB. The hot-tuning test shows that the tunability is maintained for up to 20-V peak-to-peak swing. BST capacitors utilizing the proposed technique are used in a phase-shifter design. The 2.4-GHz phase shifter exhibits high [IIP.sub.3] greater than 40 dBm. Index Terms--Barium-strontium-titanate (BST), ferroelectric capacitor, linearity, phase shifter.

A device architecture for improving the linearity of barium-strontium-titanate (BST) capacitors is proposed, analyzed, and experimentally demonstrated. The basic concept is to reduce the RF swing across the ferroelectric varactors by connecting multiple capacitors in series. With proper biasing networks, the overall device preserves its tunability. In this paper, the proposed architecture is analyzed to derive the equations that relate its quality factor and tuning speed to the design parameters. Parallel-plate BST capacitors are fabricated based on the architecture. Various measurements are performed to demonstrate the efficacy of the technique. The third-order intercept point at input (IIP3) is found to be improved by 16 dB. The hot-tuning test shows that the tunability is maintained for up to 20-V peak-to-peak swing. BST capacitors utilizing the proposed technique are used in a phase-shifter design. The 2.4-GHz phase shifter exhibits high IIP3 greater than 40 dBm. [ABSTRACT FROM AUTHOR]