Microwave frequency domain

For radiofrequency and microwave radiation there are detectors which can respond sufficiently quickly to the low frequencies (<100 GHz) involved and record the time domain specttum directly. For infrared, visible and ultraviolet radiation the frequencies involved are so high (>600 GHz) that this is no longer possible. Instead, an interferometer is used and the specttum is recorded in the length domain rather than the frequency domain. Because the technique has been used mostly in the far-, mid- and near-infrared regions of the spectmm the instmment used is usually called a Fourier transform infrared (FTIR) spectrometer although it can be modified to operate in the visible and ultraviolet regions. 

In general, the quantities being determined by microwave measurements are complex reflection and transmission coefficients or complex impedances normalized to the impedances of the transmission lines connecting a network analyser and the device-under-test (dut). In addition to linear frequency domain measurements by means of a network analyser the determination of possible non-linear device (and thus material) properties requires more advanced measure-... 

Figure 1 Two-pulse or primary ESEEM data collected for the type-1 Cu(II) site of the Fet3p enzyme. Figure 1(a) shows the time domain data recorded under the following conditions microwave frequency, 9.6883 GHz field strength, 337.0 mT pulse power, 250 W 90° pulse length, 16 ns full width at half maximum (FWHM) sample temperature, 10 K. Figure 1(b) shows the ESEEM spectrum derived from the data of Figure 1(a) by subtraction of a biexponential decay function, application of a Hamming window function, and Fast Fourier Transformation (FFT). The absolute value spectrum is displayed...

To summarize the above paragraph, trapped ions can serve as exceptional tools for new and functioning atomic clocks, in both the microwave and optical frequency domains. 

The primary electron spin-echo envelope and the corresponding frequency domain spectrum of D in PS E particles at a microwave frequency of 9.3 GHz is depicted in Fig la. It exhibits three strong lines at 1.6, 14.2 and 28.4 MHz a several of much weaker intoisity. The strong lines at 14.2 and 28.4 MHz correspond to the single and double free proton frequency, Vi and 2v,. All other lines need Either examination. 

Figure 1 Two-pulse echo envelope of PS II-enriched particles and their corresponding frequency-domain spectra at different microwave frequencies (a) v= 9.3 GHz, (b) v= 9.0 GHz, (c) v= 8.6 Ghz.

Figure 4 Numerically-calculated two-pulse echo envelopes and their corresponding frequency-domain spectra for aj, = 27.2, T = -3.1, a = 0.5. The microwave frequency is (a) 9.3 GHz, (b) 9.0 GHz and (c) 8.6 GHz.

Figure 3-Three-pulse time and frequency domain ESEEM patterns of an annealed NH4Cl-treated PSn sample prepared in H20 buffer (a,b) and an untreated PSII sample prepared in H20 buffer and illuminated at 195 K (c,d). Experimental parameters are temperature=4.2 K, microwave frequency=9.22 GHz,...

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