The first reports on experimental investigation of nonlinearities in BaxSr1-xTiO3 based ceramics date back to 1950s and early 1960s. DiDomenico et al report the first successful demonstration of a 3rd harmonic generator in 1962. Recently 2nd harmonic generation was demonstrated ; by applying DC bias. Samoilova et al. reported frequency conversion (harmonic generation) experiment in a Coplanar Waveguide (CPW) with a ferroelectric film. Where as Booth et al  uses a CPW with Ba0.3Sr0.7TiO3 film; the non-linear capacitance C by using two approaches: i) third harmonic generation; and ii) C(VDC) measurements at microwave frequencies. It was shown that the non-linear capacitance C determined from C(VDC) measurements is in excellent agreement with the one found from third harmonic generation experiment; this leads to the conclusion that ferroelectric devices might be tuned with nanosecond speeds.
To study nonlinearities Kozyrev et al designed a resonator loaded by a ferroelectric capacitor; using both a single signal as well as intermediation distortion; which confirmed previous results. Kozyrev et al also gives a simple theory for estimation of overheating of the ferroelectrics films at high power levels; and it was shown that the power handling capability of a ferroelectric tuneable filter may be as high as 3.5 W. Experiments and more detailed analysis of the microwave heating on nonlinearities are given elsewhere.
In this work; we used simple; on-chip microprobe reflection measurements to determine microwave power dependence of the capacitance of parallel-plate ferroelectric varactors. It is shown that the nonlinear parameters estimated from this experiment are in good agreement with the nonlinear parameters found from C(VDC) measurements at low frequencies. Hence; nonlinear parameters found from simple C(VDC) measurements may be used in the development of microwave devices; such as harmonic generators and mixers.
GigaHertz 2003. Proceedings from the Seventh Symposium
1. Gevorgian; S.S.; Kollberg; E.L.; â€śDo we really need ferroelectrics in paraelectric phase only in electrically controlled microwave devices?â€ť Microwave Theory and Techniques; IEEE Transactions on; Volume: 49 Issue: 11; Nov. 2001 Page(s): 2117 -2124
2. A. Kozyrev; A. Ivanov; T. Samoilova; O. Soldatenko; K. Astafev; and L. Sengupta; â€ťNonlinear response and power handling capability of ferroelectric BaxSr1-xTiO3 film capacitors and tuneable microwave devicesâ€ť; J. Appl. Phys.; Vol. 88; pp.5334-5342; 2000
3. M. DiDomenico; Jr.; D. A. Johnson; and R. H. Pantel; â€śFerroelectric Harmonic Generator and Large-Signal Microwave Characteristics of Ferroelectric Ceramicsâ€ť; J. Appl. Phys.; Vol.33; pp.1697-1706
4. A. T. Findikoglu; Q. X. Jia; D. W. Rigor; and X. D. Wu; â€śTuneable microwave mixing in nonlinear dielectric thin film of SrTiO3 and Ba0.5Sr0.5TiO3â€ś Electron. Letters; Vol. 31; pp.1814-1815; 1995.
5. T. B. Samoilva; and K. F Astafâ€™ev; T. Rivkin; and D. S. Ginley; â€śFrequency conversion in coplanar waveguide based on BaxSr1-xTiO3 filmâ€ť; J. Appl. Phys; Vol. 90; pp. 5703-5707; 2001
6. J. C. Booth; R. H. Ono; I. Takeuchi; and K. S. Chang; â€śMicrowave frequency tuning and harmonic generation in ferroelectric thin film transmission linesâ€ť; Appl. Phys Lett.; Vol. 84; pp. 718-720; 2002.
7. T. B. Samoilva; and K. F Astafâ€™ev; â€śEffect of Heat on the Nonlinearity of Plane Strontium Titanate Film Capacitor on Sapphire in a Microwave Fieldâ€ť; Technical Physics; Vol. 45; No 6; pp.759-765; 2000.
8. P. Rundqvist; A. Vorobiev; S. Gevorgian â€śNon-destructive microwave characterisation of Ferroelectric films on conductive substratesâ€ť submitted to integrated ferroelectrics.
9. A. K. Tagantsev; V. O. Sherman; K. F. Astafiev; J. Venkatesh and N. Setter; to be published in Journal of Electroceramics.