A simple, frequency-multiplied optoelectronic oscillator (OEO) based on a dual-parallel Mach–Zehnder modulator (DPMZM) is proposed and demonstrated. The generated high-frequency microwave signals have improved performance in their phase noise (PN) and signal-to-noise ratio. Two loops (master and slave) are contained in this OEO, each linked to a separate port of the DPMZM. By tuning the voltages of the modulator, a frequency-doubled radio frequency signal is generated in the slave loop and a frequency-quadrupled signal is generated in the master loop. In these experiments, the microwave signals have good performance in purity and PN. The PN of the generated frequency-doubled and frequency-quadrupled signals is −113.3 dBc / Hz@10 kHz and −106.1 dBc / Hz@10 kHz, respectively.
Proc. SPIE. 9796, Selected Papers of the Photoelectronic Technology Committee Conferences held November 2015
KEYWORDS: Mathematical modeling, Solar radiation models, Data modeling, Skin, Far infrared, Infrared radiation, Radiation effects, Solar radiation, Performance modeling, Thermal modeling, Atmospheric modeling, Temperature metrology
The characteristic of the self-infrared radiation of airplane-skin is very important for the stealth performance of airplane. Based on the theory of the airplane-skin temperature field, the distribution of the atmospheric temperature field and the principle of the black-body radiation function the self-infrared radiation model was established. In specified flight conditions, the influence of the atmospheric temperature, the speed of flight, the emissivity and the sight angle detection on the self-infrared radiation of the airplane skin were analyzed. Through the simulation of infrared radiation, some results under different flight states are obtained. The simulation results show that skin infrared radiation energy mainly concentrate on the far infrared wavebands, and various factors have different effects on the infrared radiation of skin. This conclusion can help reduce the infrared radiation and improve the stealth performance of airplane in the engineering design and the selection of flight conditions.
Using polarimetric information of the camouflaged target surface to identify camouflage has been a hot research area in camouflage detecting. The main method is to use the difference in the degree of polarization(DOP) between background and target to add the contrast ratio of them. The measurement of the DOP has some requirements on the intensity of reflected radiation. In case of low reflected radiation intensity, the difference in the DOP for different materials is not so distinguishable. In addition, the linear degree of polarization is largely under the effects of detection angle and surface roughness, so it is hard to differentiate the degree of polarization when the targets with similar surface roughness are detected at the same detection angle. By analyzing the elements affecting the reflected electromagnetic radiation amplitudes and phase on the camouflaged target surface, this article makes a research on the polarization character of reflected radiation A method on camouflaged target recognition directly or indirectly by taking the angle of ellipsometry (AOE) imaging under the linear polarized light. The function model of the angle of incidence, complex refractive index and AOE was modeled, then the model was simulated by MATLAB and the results showed it can describe the distribution properties of AOE. A new thought for the approach of identifying camouflaged target recognition by detecting polarimetric information was proposed, and it has a deep theoretical and practical significance in camouflaged target recognition.