Piezoelectric Transducer Phase Research Articles

Optical profiler based on spectrally resolved white light interferometry

A white light interferogram can be decomposed into its constituent monochromatic interferograms using a spectrograph. By imaging the white light interferogram on the entrance slit of the spectrograph, the intensities of the monochromatic components can be accessed at its output plane by the pixels of a CCD detector along the direction of dispersion. For a given optical path difference (OPD) in the interferometer, the phases of these constituents are different and linearly related to the wave number of the constituent spectral component. If the phases of all the constituents are determined, the OPD can be obtained as the slope of the phase versus wave number linear fit. Since the OPD is related to the height of the test object at a point, a line profile of the object can be determined if the OPD is measured along the pixels of the CCD parallel to the entrance slit of the spectrograph. To get at the line profile, we must therefore determine the optical phase at all the pixels of the CCD detector. The phase-shifting technique is an obvious choice for this. A piezoelectric transducer (PZT) phase shifter is most common in the application of the phase-shifting technique to monochromatic interferometry. We present the experimental result based on our recent proposal that the conventional PZT phase shifting, although nonachromatic, can be used for this application as well with success.

Analysis and optimization of a phase shifter controlled by a piezoelectric transducer

This paper introduces a method for analyzing and optimizing a phase shifter controlled by a piezoelectric transducer (PET). To analyze the multilayer microstrip structure of the PET-controlled phase shifter, new equivalent single-layer (ESL) equations for the phase shift and loss calculations are developed and confirmed with spectral-domain analysis (SDA) of the moment method. A parametric analysis is accomplished with ESL equations and SDA, and optimization guidelines are suggested. An optimized PET phase shifter is demonstrated to operate up to 40 GHz with a maximum total loss of 4 dB and phase shift of 480/spl deg/. Measured results agree very well with calculations showing substantially smaller control voltage, size, and dispersion, as compared to previously published data. This new analysis and optimization technique for the PET-controlled phase shifter should be useful in the design of phased-array antennas and tunable microwave circuits.

A low-cost 8 to 26.5 GHz phased array antenna using a piezoelectric transducer controlled phase shifter

A new phased array antenna of wide bandwidth and good beam scanning angle has been developed using a low cost multiline phase shifter controlled by a piezoelectric transducer (PET) and a stripline fed Vivaldi antenna array. The multiline progressive PET phase shifter has a low perturbation loss of less than 2 dB and a total loss of less than 4 dB up to 40 GHz with a maximum phase shift of 480/spl deg/. The proposed phased array antenna consists of four E- or H-plane Vivaldi antennas, a PET phase shifter, and a power divider. The phased array shows a wide beam scanning capability of /spl plusmn/27/spl deg/ over a wide bandwidth from 8 to 26.5 GHz covering X, Ku, and K bands.