set from the 5.5 GHz, when the signal is injected, the phase noise of the ILFD is about -132.25 dBc/Hz, while the phase noise of the injection-reference is -125.88 dBc/Hz. At low offset frequency, the phase noise of the locked ILFD is smaller than the injection signal by about 6 dB. Figure 13 shows the measured output spectra of the divider before and after the locked conditions in the 2 mode. The locked output spectrum shows a lower phase noise. Table 1 shows the performance summary of the proposed ILFD. Tables 2 and 3 show the performance comparison between pub- lished ILFDs in the divide-by-3 and -2 mode, respectively. 4. CONCLUSION This article proposes a new CMOS LC-tank ILFD circuit and the chip has been successfully implemented in the TSMC 0.18-m CMOS process. The differential ILFD consists of double-cross- coupled VCO and a composite resonator, where a pair of switched inductors with an inductor in series with an injection MOSFET is used. In the differential injection mode, the ILFD can have the division ratio of 1 and 3, in the single injection mode, the ILFD can have the division ratio of 2, other higher modulo is beyond the limit of experimental set up. ACKNOWLEDGMENTS The authors thank the Staff of the CIC for the chip fabrication and technical supports. REFERENCES 1. J. Craninckx and M. Steyaert, Wireless CMOS frequency synthesizer design. Kluwer, London, UK, 1998. 2. Y.-H. Chuang, S.-H. Lee, R.-H. Yen, S.-L. Jang, J.-F. Lee, and M.-H. Juang, A wide locking range and low voltage CMOS direct injection- locked frequency divider, IEEE Microwave Wireless Compon Lett 16 (2006), 299 –301. 3. S.-L. Jang and C.-F. Lee, A wide locking range LC-tank injection locked frequency divider, IEEE Microwave Wireless Compon Lett 17 (2007), 613– 615. 4. W.-Z. Chen and C.-L. Kuo, 18GHz and 7GHz superharmonic injection- locked dividers in 0.25um CMOS technology, In: Proceedings of the European Solid-State Circuits Conference (ESSCIRC), 2002, pp. 89 – 92. 5. J. Jeong, S. Kim, W. Choi, H. Noh, K. Lee, K.-S. Seo, and Y. Kwon, W-band divide-by-3 frequency divider using 0.1 m InAlAs/InGaAs metamorphic HEMT technology, Electron Lett 41 (2005), 1005–1006. 6. S.-L. Jang, W. Yeh, and C.-F. Lee, A low power CMOS divide-by-3 LC-tank injection locked frequency divider, Microwave Opt Technol Lett 50 (2008), 259 –262. 7. P. Wambacq and W. Sansen, Distortion analysis of analog integrated circuits, Kluwer, Dordrecht, 1998. 8. S.-L. Jang, C.-F. Lee, and W.-H. Yeh, A divide-by-3 injection locked frequency divider with single-ended input, IEEE Microwave Wireless Compon Lett 18 (2008), 142–144. 9. M. Tiebout, A CMOS direct injection-locked oscillator topology as high-frequency low-power frequency divider, IEEE J Solid-State Circ 39 (2004), 1170 –1174. © 2009 Wiley Periodicals, Inc. MICROWAVE PROPERTIES OF ARROWROOT AND ITS MEDICAL APPLICATIONS Ullas G. Kalappura, Robin Augustine, and K. T. Mathew Microwave Tomography and Materials Research Laboratory, Department of Electronics, Cochin University of Science and Technology, Cochin- 682022, Kerala, India; Corresponding author: ktm@cusat.ac.in Received 2 September 2008 ABSTRACT: Arrowroot (Maranta arundinacea) is an edible starch, commercially available as powder, prepared from the roots of the plant family Marantaceae. Arrowroot is well known for its medicinal effects and use as chief ingredient in infant cookies. Arrowroot in film form is prepared and its microwave absorption characteristics, permittivity, loss factor, conductivity, skin depth, and heating coefficient are analyzed. The results are quite promising and can be concluded that arrowroot in film form is a potential candidate for several applications in medical field, when compared with well studied chitosan film. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1267–1270, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24304 Key words: arrowroot; dielectric parameters; microwave absorption; drug delivery 1. INTRODUCTION Arrowroot is from the family Marantaceae [1]. It is valued chiefly for its thickening properties. Arrowroot (ARROW) is most com- monly used as a chief ingredient in baby food, as substitute for talcum in baby powder and body powder. Because of its medicinal properties [2], it is considered to be an effective antidote to vegetable poisons. An interesting pilot study on the use of arrow- root as treatment for diarrhoea in irritable bowel syndrome patients by C. Cooke et al. [2] shows that arrowroot is very effective in treatment of diarrhoea and plays a significant role in reducing daytime bowel frequency. Material characterization using microwaves is a solid field where microwave properties of materials are studied. By studying the dielectric properties [3, 4], several biological effects can be studied. For instance, microwaves are widely used in the field of imaging for finding malicious tissues and tumors. These tech- niques use tissue characterization based on complex permittivity. The dielectric properties of the malignant tissue will be different from that of the normal tissue. Several advancements have been made on the dielectric property study of materials. Here, we are performing the well known cavity perturbation technique [5] to study the dielectric properties of arrowroot. The properties such as permittivity and loss factor are significant in determining material properties. So stress is given on finding these values. Also absorp- tion characteristic for a frequency range of 2–3 GHz is plotted. This gives an amount of absorbed power at different microwave frequencies and will be helpful in the study of effect of nonioniz- ing radiation [6] on chitosan and arrowroot. 2. MATERIAL PREPARATION AND MEASUREMENTS Arrowroot powder is prepared from the root of arrowroot plant. The root is dried, powdered, thoroughly washed, and filtered to obtain arrowroot powder. This is commercially available in the market. Arrowroot is dissolved in water and the solution is heated to obtain the gel which is used to obtain arrowroot film. The film prepared is transparent and can be of various thicknesses. Micro- wave drying was used as it provided uniform heating. TABLE 3 Comparison of Divide-by-2 ILFDs Ref. Tech. (m) Pin (dBm) V DD (V) Pdiss. (mW) Locking Range (GHz) [2] 0.18 0 0.75 4.5 3.14–4.63 [9] 0.13 7 1.5 23 14.2–17.2 This work 0.18 0 1.8 4.97 9.48–11.48 DOI 10.1002/mop MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 51, No. 5, May 2009 1267