Tunable dielectric resonator with circumferentially magnetized ferrite disks
Electronically tunable dielectric resonator containing circumferentially magnetized ferrite elements has been investigated. The structure of the resonator has been analysed to obtain the optimal parameters. The resonator was constructed whose resonant frequencies can be switched by short current pulses between two stable values that differ in frequency up to 25 MHz with Q-factor value about 4200.
Optimization of Spurious Response in Dielectric Resonator Tunable Filters
Methods of tunable filters spurious response improvement are described. Dielectric resonator based filters with ferrite elements suffer from spurious resonances located close to the useful passband. Optimization of the resonator structure as well as application of TEM resonators leads to significant improvement. Design methods and measured results are provided.
Observations of nearshore infragravity waves: Seaward and shoreward propagating components
[1] The variation of seaward and shoreward infragravity energy fluxes across the shoaling and surf zones of a gently sloping sandy beach is estimated from field observations and related to forcing by groups of sea and swell, dissipation, and shoreline reflection. Data from collocated pressure and velocity sensors deployed between 1 and 6 m water depth are combined, using the assumption of cross-shore propagation, to decompose the infragravity wave field into shoreward and seaward propagating components. Seaward of the surf zone, shoreward propagating infragravity waves are amplified by nonlinear interactions with groups of sea and swell, and the shoreward infragravity energy flux increases in the onshore direction. In the surf zone, nonlinear phase coupling between infragravity waves and groups of sea and swell decreases, as does the shoreward infragravity energy flux, consistent with the cessation of nonlinear forcing and the increased importance of infragravity wave dissipation. Seaward propagating infragravity waves are not phase coupled to incident wave groups, and their energy levels suggest strong infragravity wave reflection near the shoreline. The cross-shore variation of the seaward energy flux is weaker than that of the shoreward flux, resulting in cross-shore variation of the squared infragravity reflection coefficient (ratio of seaward to shoreward energy flux) between about 0.4 and 1.5.