Design of compact microstrip lowpass elliptic filter with wide stop band using invasive weed optimization
In this paper, the invasive weed optimization technique is used to design a compact microstrip elliptic low pass filter with very high order suppression response. This method enhances the filter stop band bandwidth more than 8.5 f3dB and achieves 47% compactness compared with the traditional elliptic filter. The measurement results of the final optimized fabricated filter are in good agreement with the simulation ones.
Compact microstrip low-pass filter design with ultra-wide reject band using a novel quarter-circle DGS shape
─ A novel quarter-circle defected ground structure shape is introduced in this paper to design and implement an ultra-wide reject band low-pass filter (LPF). Moreover, an equivalent circuit model (ECM) is presented. The proposed LPF has small size and, a low insertion loss and a return loss less than -20 dB. Also, a round -20 dB suppression level ranging from 4 GHz to more than 20 GHz is achieved. The simulated results obtained by ECM and full-wave EM show good agreement with the measured ones. Index Terms ─ Compensated microstrip line, defected ground structure (DGS), low-pass filter (LPF), quarter-circle (QC) shape.
Experimental study on ground vibration of blasting the boulder with tandem shaped charging warhead
Hazardous effects of blasting the boulder with the new breaking-blasting equipment-tandem shaped charging warhead are mainly air shock wave, seismic wave and blast slung shot. Blast-induced ground vibration is one of the inevitable effects and may cause substantial damage to nearby structures. Started from the formation process and mechanism of ground vibration to study the seismic wave, the research attained curve of vibration velocity of monitoring points by TC-4850 and carried out differential and fast Fourier transform analysis of the curve. And the results concluded that blasting vibration with tandem shaped charging warhead mainly comes from prime charge; the attenuation law can be predicted by Sadev’s Formula. Explosion vibration frequency range is 20-150 Hz, while with the increase of distance from the blasting center, blasting vibration intensity attenuates rapidly, vibration duration increases and vibration frequency gradually reduces. Compared with general rock blasting, its attenuation rate of blasting vibration is faster with higher frequency and smaller impact on buildings, but the harm effects should not be ignored for the special application environment.