Liquid Metal-Enabled Filtering Switches and Switchplexers

The via-pad-slot (VPS) structure, as the switchable element, has been used to demonstrate a single-pole-triple-throw (SPTT) filtering switch and a switchplexer. The VPS can be flexibily switched using liquid metal (LM) or high dielectric constant materials to either cover or uncover the slot. Since the LM only moves on the surface of the VPS and the substrate-integrated waveguide (SIW), the implementation and actuation of the LM is simple and does not cause excessive loss on the device. In the switchplexer design, all channels can be switched on and off to form filters or multiplexers of various channel combinations. Additional transmission zeros (TZs) can be generated by the loaded, partially switched-off channel. The generation of the TZs was discussed and analyzed using coupling matrix approach. The demonstrated &lt;italic&gt;X&lt;/italic&gt;-band (9.56&amp;#x2013;10.44 GHz) cross-shaped SPTT fifth-order filtering switch exhibits a suppression level of better than 40 dB at 8 and 12 GHz, an insertion loss (IL) of 1.55 dB at 10 GHz, and an isolation level of 58 dB at 10 GHz. The &lt;italic&gt;X&lt;/italic&gt;-band switchplexer operates at three frequency bands, e.g., 11.08&amp;#x2013;11.55 GHz, 10.61&amp;#x2013;10.99 GHz, and 9.76&amp;#x2013;10.33 GHz. The LM-enabled VPS-based switchable element can be integrated with other multifunctional circuits and systems for channel control and reconfiguration.</p

Correlation function of flavored fermion in holographic QCD

By using the gauge-gravity duality, we investigate the correlation function of flavored fermion in the $\mathrm{D}_{p}/\mathrm{D}_{p+4}$ model as top-down approaches of holographic QCD for $p=4,3$. The bulk spinor, as the source of the flavored fermion in QCD, is identified to the worldvolume fermion on the flavor $\mathrm{D}_{p+4}$-branes and the standard form of its action can be therefore obtained by the T-duality rules in string theory. Keeping this in hand, we afterwards generalize the prescription for two-point correlation function in AdS/CFT dictionary into general D-brane backgrounds and apply it to the case of $p=4,3$, i.e. the D4/D8 and D3/D7 approach respectively. Resultantly, our numerical calculation with the bubble background always displays discrete peaks in the correlation functions which imply the bound states created by the flavored fermions as the confinement in QCD. With the black brane background, the onshell condition illustrated by the correlation function covers basically the dispersion curves of fermion obtained by the hard thermal loop approximation in the hot medium. In this sense, we conclude remarkably that our top-down approach in this work could reveal the fundamental properties of QCD both in the confined and deconfined phase.Comment: 41 pages; 11 figures; 1 table; fix Figure 7 and Figure 1