Near resonance vibration isolation on a levered-dual response(LEDAR)Coulomb-damped system by differential preloads/offsets in linear springs

The levered-dual response(LEDAR)Coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear springs.It takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration isolation.The isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without guiderails.The compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the potential threshold.The isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate connector.The observed near resonant isolation thus makes the LEDAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simultaneous harvesterisolation functions and passive functions at extreme frequencies.

Quintuple Band Antenna for Wireless Applications with Small Form Factor

A coplanar waveguide-fed quintuple band antenna with a slotted circular-shaped radiator for wireless applications with a high isolation between adjacent bands is presented in this paper.The proposed antenna resonates at multiple frequencies with corresponding center frequencies of 2.35,4.92,5.75,6.52,and 8.46 GHz.The intended functionality is achieved by introducing a circular disc radiator with five slots and a U-shaped slot in the feed.The proposed antenna exhibits coverage of the maximum set of wireless applications,such as satellite communication,worldwide interoperability for microwave access,wireless local area network(WLAN),long-distance radio telecommunications,and X-band/Satcom wireless applications.The simulation and measurement results of the proposed fabricated antenna demonstrate the high isolation between adjacent bands.A stable realized gain with an advantageous radiation pattern is achieved at the operating frequency bands.The proposed simple design,compact structure,and simple feeding technique make this antenna suitable for integration in several wireless communication applications,where the portability of devices is a significant concern.The proposed antenna is anticipated to be an appropriate candidate for WLAN,long-term evolution,and fifth-generation mobile communication because of its multi-operational bands and compact size for handheld devices.