We have studied the time series of full disk integrated soft and hard X-ray emission from the solar corona during 2004 January to 2008 December, covering the entire descending phase of solar cycle 23 from a global point of view. We employ the daily X-ray index derived from 1 s cadence X-ray observations from the Si and CZT detectors of the "Solar X-ray Spectrometer" mission in seven different energy bands ranging between 6 and 56 keV. X-ray data in the energy bands 6-7, 7-10, 10-20, and 4-25 keV from the Si detector are considered, while 10-20, 20-30, and 30-56 keV high energy observations are taken from the CZT detector. The daily time series is subjected to power spectrum analysis after appropriate correction for noise. The Lomb-Scargle periodogram technique has shown prominent periods of ∼13.5 days, ∼27 days, and a near-Rieger period of ∼181 days and ∼1.24 yr in all energy bands. In addition to this, other periods like ∼31, ∼48, ∼57, ∼76, ∼96, ∼130, ∼227, and ∼303 days are also detected in different energy bands. We discuss our results in light of previous observations and existing numerical models.

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A low-loss 10 GHz range surface acoustic wave (SAW) filter is investigated. It is fabricated on 128° Y-X LiNbO3 using the electron beam direct writing and lift-off process. The Al electrode with a width of 95 nm and a thickness of 30 nm is obtained successfully. In order to simulate the characteristics of a ladder type filter with an equivalent circuit model, the parameters of an equivalent circuit model for a thick Al film in the 5 GHz range (thickness is 0.08 λ, λ= 0.75 µm, λ is the wavelength of SAW) is determined experimentally. The experimental results of the ladder type filter in the 10 GHz range show low loss characteristics. The minimum insertion loss of 3.7 dB is obtained.