Poster Session Radiators of Powerful UWB Pulses Developed by AIHT of RAS V.E. Ostashev, E.F. Lebedev, A.V. Ul’yanov, and V.M. Fedorov Associated Institute for High Temperature of Russian Academy of Sciences (AIHT of RAS) 13/2, Izhorskaya str., Moscow, 127412, Russia Phone: 8(495) 485-7944, E-mail: [email protected] Abstract – The description of six experimental models of UWB radiators with excitement's generators of the semiconductor type is presented. Duration of radiation pulse is from 70 ps to 1 ns, pulse repetition rate is from 100 to 3 105 pps, effective radiated pulse power is up to 400 MW, and effective average power – up to 90 W. The measured E-fields and calculated energy spectrums of the radiations are presented. Values of effective parameters of radiation for considered models are presented for the interval of effectively radiated frequencies. 1. Introduction The object of the proposed study is UWB radiator. The questions of the creation and practical use such radiators are discussed long ago and broadly. The physical problem when creation of any energy converter is an achievement to high efficiency of her transformation. The purpose of the work consisted in creation different models of UWB radiators, presentation local and efficient parameters of the radiation and comparison of the models on these parameters. The generators excite the antennae of aperture type. All antennae join to generator directly, without additional feeder. Limiting parameters of radiators with the use of these generators are discussed in [2]. The converter of a strip line type was used as a sensor of E-field strength in free space [3].Typical sensor sensitivity was 0.3...0.5 V/(kV/m). Possible time of sensor registration was 4 ns and it self rise time 20...30 ps. Registration of the voltage from sensor of pulsed E-field was conducted with the use of pulsed and stroboscopic digital oscilloscopes with frequency band up to 18 GHz. Model M1. The main parameters of the generator of excitement of antenna were: amplitude 10 kV (2 MW on 50 Ohm load), front of the pulse 50...60 ps, pulse repetition rate up to 105 pps. The average power of generator consumption on maximum frequency was 240 W. The antenna of radiator was horn type (four horns connected in parallel). Input impedance of antenna is equal to nearly 50 Ohm, size of the full aperture – 16 16 cm. The view of M1 is shown in Fig. 2. 2. Laboratory models of UWB radiator produced by AIHT of RAS The general feature of models. Models contain generators of the pulsed voltages of the semiconductor type of the development “FID-Technology” (www.fidtechnology.com; [1]). Typical curve of voltage for the used generators is shown in Fig. 1. 10 8 Fig. 2. Model M1. Antenna (16 16 cm) and generator of excitation with a peak power 2 MW Ug, kV 0.9 Measured pulse of E-field strength and energy spectrum of this signal are shown in Fig. 3. 9.5 kV 100 ps On figure of spectral density q (f) there is shown, 4 as density of energy of the radiation pulse is defined in 0.1 the given spectral interval f . Here, for example, the 2 interval of effectively radiated frequencies was cho00 0.5 1 1.5 2 2.5 sen. This interval has been defined on level in a half of Time, ns the amplitude of the spectral density. Fig. 1. Typical curve of the unipolar pulse of the voltage for Model M2. The main parameters of the generator the generators of “FID-Technology” of excitement of antenna were: amplitude 10 kV The typical amplitudes of output pulse for these (2 MW on 50 Ohm load), front of the pulse nearly generators are 1...100 kV; the pedestal of the pulse is 100 ps, FWHM 370 ps, pulse repetition rate up to 10...20% from its amplitude. The pulse repetition rate 105 pps. The average power of generator consumption is 103...106 pps and the average power consumption is on maximum frequency was 250 W. Antenna of radiator is of horn type, aperture is equal to 200…300 W. The efficiency of energy transformation is not worse than 40%. equal to 14 27 cm. The view of M2 is shown in Fig. 4. 455 6 7.6 kV High Pover Microwaves 2 0 –2 –4 0 2 0.1 g, nj/m2 MHz 8 7 6 f 5 4 3 2 1 0 2 4 6 8 10 12 14 Frequency, GHz 1.6 1.2 0.8 0.4 0 0.2 0.3 Time, ns 0 Fig. 6. Model M3 of UWB radiator Fig. 3. Model M1. Pulse of E-field strength in 3 meters from antenna's aperture and energy spectrum of this pulse Measured pulse of E-field strength and energy spectrum of this signal are shown in Fig. 7. E, kV/m 10 2 8 1 Fig. 4. Model M2 with the device of repetition rate control 6 0 4 –1 2 –2 0 Measured pulse of E-field strength and energy spectrum of this signal are shown in Fig. 5. 0 –1 –2 0 0.2 0.4 0.6 Time, ns g, nj/m2 MHz 0.6 0.5 0.4 0.3 0.2 0.1 00 f 1 2 3 4 5 Frequency, GHz 1.4 1.2 1 0.8 0.6 0.4 0.2 6 70 2 3 Time, ns 50 4 25 10 20 8 15 f 10 6 4 5 0 2 0 0,5 1 1,5 Frequency, GHz 2 0 Fig. 7. Model M3. Pulse of E-field strength in 7.3 m from antenna's aperture and energy spectrum of this pulse Density of energy, mcJ/m2 1 1.4 1,2 1 0.8 0.6 0.4 0.2 0.8 0 1 g, nj/m2 MHz Density of energy, mcJ/m2 E, kV/m 2 Density of energy, mcJ/m2 4 8 7 6 5 4 3 2 1 0.40 Density of energy, mcJ/m2 6 (16 MW on 50 Ohm load), front of the pulse nearly 100 ps, FWHM 1 ns, pulse repetition rate up to 104 pps. The average power of generator consumption on maximum frequency was 300 W. Antenna of radiator is of dipole type, unidirectional (with reflector) with impedance 50 Ohm. The choice of such antenna was conditioned by need to displace the energy spectrum of the radiation in low frequency area. The size of aperture is equal to 50 50 cm. The view of M3 is shown in Fig. 6. Density of energy, mcJ/m2 E, kV/m Density of energy, mcJ/m2 8 Fig. 5. Model M2. Pulse of E-field strength in 6.6 m from antenna's aperture and energy spectrum of this pulse Model M3. The main parameters of the generator of excitement of antenna were: amplitude 28 kV Model M8. The main parameters of the generator of excitement of antenna were: amplitude 45 kV (40 MW on 50 Ohm load), front of the pulse nearly 120 ps, pulse repetition rate up to 200 pps. The average power of generator consumption on maximum frequency was 40 W. Antenna of radiator was similar model M2. The view of pulse generator of M8 is shown in Fig. 8 and measured pulse of E-field strength and energy spectrum of this signal are shown in Fig. 9. Eight such models built in active antenna array with electronic device of the automatic support the synchronism [4]. Far-field voltage factor of this array 456 Poster Session repetition rate up to 3 105 pps. The average power of generator consumption on maximum frequency was 170 W. Density of energy, mcJ/m2 was 455 kV and effective radiated power nearly 7 GW. E, kV/m 30 250 20 200 10 150 0 100 –20 0 Fig. 8. Pulse generator for model M8 3 2.5 2 1.5 1 0.5 00 0.3 1.2 1.5 f 1 2 3 4 5 Frequency, GHz 7 6 5 4 3 2 1 6 70 0.2 0.4 0.6 0.8 Time, ns 10 g, nj/m2 MHz 1.4 1.2 1 0.8 0.6 0.4 0.2 0 250 200 f 150 100 50 2 3 4 5 60 Frequency, GHz Fig. 11. Model G70. Pulse of E-field strength in 5 m from antenna's aperture and energy spectrum of this pulse Density of energy, mcJ/m2 0.6 0.9 Time, ns g, nj/m2 MHz 0 7 6 5 4 3 2 1 0 Density of energy, mcJ/m2 E, kV/m 3 2 1 0 –1 –2 –3 –4 50 Density of energy, mcJ/m2 –10 0 1 Antenna of radiator was similar model M2. The view of pulse generator of G500 is shown in Fig. 12. Fig. 13 shows the local parameters of radiation. Fig. 9. Model M8. Pulse of E-field strength in 16 m from antenna's aperture and energy spectrum of this pulse Model G70. The main parameters of the generator of excitement of antenna were: peak power 65 MW on 50 Ohm load, front of the pulse nearly 130 ps, pulse repetition rate up to 100 pps. The average power of generator consumption was 40 W. Antenna of radiator is of horn type, aperture is equal to 27 27 cm. The view of G70 is shown in Fig. 10. E, kV/m 0.6 100 0.4 80 0.2 60 0 40 –0.2 20 0 0.2 0.4 0.6 Time, ns 0.8 10 100g, nj/m2 MHz 4 100 3 80 2 1 Measured pulse of E-field strength and energy spectrum of this signal are shown in Fig. 11. Model G500. The main parameters of the generator of excitement of antenna were: amplitude 3 kV, front of the pulse nearly 120 ps, FWHM 500 ps, pulse Density of energy, mcJ/m2 –0.4 Fig. 10. Model G70: pulse power of excitation is equal 65 MW, aperture of horn antenna 27 27 cm Density of energy, mcJ/m2 Fig. 12. Pulse generator for model G500 60 40 20 2 3 4 5 6 7 80 Frequency, GHz Fig. 13. Model G500. Pulse of E-field strength in 6.6 m from antenna's aperture and energy spectrum of this pulse 457 00 1 f High Pover Microwaves 3. Parameters of the radiation of models in band of effectively radiated frequencies Some results with corresponding to explanations are shown in Figures 14–17. Value of field-distance production is basically defined by voltage of excitement of antenna and the size of its aperture (Fig. 14). is equal to frequency of pulses repetition), average within the range of effectively radiated frequencies. This power is connected with the power of EM radiation in effective frequency interval and the quantity of spectral lines in given interval which is equal to pulse ratio. 2.5 120 2 100 E R, kV PL, mW 1.5 80 1 60 110 40 20 0 11 М2 15 М3 0 M8 G70 G500 0.4 1 2 0.2 0.1 M1 M2 M3 M8 G70 G500 Fig. 15. Attitude of efficient power of the radiation to power consumption: 1 – for full radiated power; 2 – for power in band of effectively radiated frequencies The model M1 was the best on effective power of EM radiation but the model M3 has been characterized the maximum value of average spectral density (Fig. 16). The model M1 is the best on effective power of EM radiation but the model M3 is characterized of the maximum value of average spectral density of radiation (Fig. 16). The last was connected with the comparatively narrow frequency band (nearly 400 MHz for the model M3 vs 4 GHz for model M1). 120 100 1, W 2, mW/MHz 80 60 40 20 0 М1 М2 М3 М1 М2 М3 M8 G70 G500 Fig. 17. Power of the EM radiation in single spectral line, average within the range of effectively radiated frequencies The model M1 was the best on efficiency of the energy conversion to EM radiation (Fig. 15). 0 1.6 1.2 0.0003 0.0003 3,3 Fig. 14. Field-distance production 0.3 1.7 0.5 56 19 М1 2.4 M8 G70 G500 Fig. 16. Effective power of EM radiation in the band of effectively radiated frequencies (1) and her average spectral density (2) Figure 17 shows power of the EM radiation in single spectral line (or into the frequency interval which 4. Conclusion Six models of radiator with generators of excitement of the semiconductor type with pulsed power from 0.2 to 65 MW have been created. The parameters of pulse of radiation for these models and their effective parameters are presented. These parameters are the base for designing UWB radiators with semiconductor generators for antenna excitation. The alike modules of radiators can be timed and form the powerful antenna arrays. The models can be used for study radio and electronic equipments on resistance to influence the pulsed EM radiation. References [1] V.M. Efanov, P.M. Yarin, and A.V. Kricklenko “New Generation of High Voltage Picosecond Generators Based on FID Technology”, in Proc. of the IEEE AP-S Intern. Symp. on UNSC/URSI and AMEREM Meetings, 2006, p. 72. [2] V.Ye. Ostashev, A.V. Ul'yanov, and V.M. Fedorov, “The Limiting Possibilities of Generating UWB Radiations with the Use of Powerful Semiconductor Generator Excitement”, in Proc. 9th All-Russian scientifically-practical conf. “Actual problems of protection and safety”, 2006, p. 329. [3] S.A. Podosenov, K.Yu. Sakharov, Ya.G. Svekis, and A.A. Sokolov, “Linear Two-Wire Transmission Line Coupling to an External Electromagnetic Field. Part II: Specific Cases, Experiment”, IEEE Transactions on Electromagnetic Compatibility 37, 566 (1995). [4] V.M. Fedorov, I.V. Grekhov, E.F. Lebedev et al., “Active Antenna’s Array with Control and Stabilization of Regimes of Synchronizing for UWB Video-Pulses”, Izvestiya Vuzov (Physics) 11, 405 (2006). 458

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