Fully Flexible, Polymer based Microwave Devices Part II: Flexible Antennas and Performance Evaluation

In this work, we have investigated polymer-based flexible antennas from commercial and modified polymers, which are competitive to rigid PCB technology. Classical designs of the patch and bow-tie antennas have been realized and showed that the realized gain can get up to 9.16dBi for the patch and 7.9dBi for the bow-tie antennas. The effects of the dielectric loss and conductivity on the antennas’ performance in S-band have been analyzed in order to find limits for further material engineering and the optimum trade-off between microwave and mechanical performance. The bending effects have been investigated, and it has been found that E-plane bend inside can boost the antenna gain from 8.6dBi to 10.1dBi with the frequency shift from 2.5 GHz to 2.4 GHz for the patch and 7.9dBi to 11.3dBi at 3.1 GHz for the bow-tie antennas. The non-classical π-shaped conductors’ edges lead to additional fringing fields, which have an effect on the antenna’s gain and can be explored and exploited for further performance improvements. The new recipes for low-loss, low-Dk dielectric materials, and chemical integration between conducting

Fully Flexible, Polymer based Microwave Devices Part II: Flexible Antennas and Performance Evaluation

In this work, we have investigated polymer-based flexible antennas from commercial and modified polymers, which are competitive to rigid PCB technology. Classical designs of the patch and bow-tie antennas have been realized and showed that the realized gain can get up to 9.16dBi for the patch and 7.9dBi for the bow-tie antennas. The effects of the dielectric loss and conductivity on the antennas’ performance in S-band have been analyzed in order to find limits for further material engineering and the optimum trade-off between microwave and mechanical performance. The bending effects have been investigated, and it has been found that E-plane bend inside can boost the antenna gain from 8.6dBi to 10.1dBi with the frequency shift from 2.5 GHz to 2.4 GHz for the patch and 7.9dBi to 11.3dBi at 3.1 GHz for the bow-tie antennas. The non-classical π-shaped conductors’ edges lead to additional fringing fields, which have an effect on the antenna’s gain and can be explored and exploited for further performance improvements. The new recipes for low-loss, low-Dk dielectric materials, and chemical integration between conducting

Saturn’s nightside ring current during Cassini’s Grand Finale

<p>During Cassini’s Grand Finale proximal orbits, the spacecraft traversed the nightside magnetotail to ~21 Saturn radii.  Clear signatures of Saturn’s equatorial current sheet are observed in the magnetic field data.  An axisymmetric model of the ring current is fitted to these data, amended to taken into account the tilt of the current layer by solar wind forcing, its teardrop-shaped nature and the magnetotail and magnetopause fringing fields.  Variations in ring current parameters are examined in relation to external driving of the magnetosphere by the solar wind, and internal driving by the two planetary period oscillations (PPOs) and compared with dawn and dayside regimes.  The relative phasing of the PPOs determines the ring current’s response to solar wind conditions. During solar wind compressions when the PPOS are in antiphase, magnetospheric storms are triggered and a thick partial ring current is formed on the nightside, dominated by hot plasma injected by tail reconnection.  However, during solar wind compressions when the PPOs are in phase, the magnetosphere shows only a ‘minor’ response and a partial ring current is not observed. During solar wind rarefactions an equatorial ‘magnetodisc’ configuration is observed in the dayside/dawn/nightside regions, with similar total currents flowing at these local times.  This partial ring current should close partly via magnetopause currents and possibly via field-aligned currents into the ionosphere.  During very quiet intervals of prolonged solar wind rarefaction, a thin current sheet with an enhanced current density is formed, indicative of a ring current dominated by cool, dense, Enceladus water group ions.</p>

Experimental energy resolution of a paracentric hemispherical deflector analyzer for different entry positions and bias simulated in SIMION

Results from the simulation of a biased paracentric hemispherical deflector analyzer (HDA) with injection lens are presented. The finite differences electron optics software SIMION was used to perform Monte Carlo type trajectory simulations in an effort to investigate the focusing effects of the HDA entry and exit fringing fields which are used to improve energy resolution - a novel feature of this type of analyzer. Comparisons to recent experimental results are also presented. Biased paracentric HDAs represent a novel class of HDAs, which use the lensing action of the strong fringing fields at the HDA entry, to restore the first order focus characteristics of ideal HDAs in a controlled way. The improvement in energy resolution and transmission without the use of any additional fringing field correction electrodes is of particular interest to modern analyzers using position sensitive detectors.