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In this article, a novel design approach to triple-resonant, circular sector patch antenna with wideband null frequency scanning functionality is advanced. At first, the operation principle of null frequency scanning functionality is revealed by the simplest, straight electric dipole under multiple resonances. Then, a triple-resonant circular sector patch antenna is designed based on a double-wavelength prototype magnetic dipole by synthesizing it usable resonant modes. As synthesized, the resonant TM12/17,1, TM36/17,1, and TM60/17,1 modes within a 255° circular sector patch radiator can be simultaneously excited, properly perturbed, and then used to realize a wideband null frequency scanning functionality. Next, different prototype antennas are designed and fabricated and experimentally verified the design approach on a single layered air substrate. As finally demonstrated, the antenna can exhibit a null frequency scanning range from $\theta =+ 35^{\circ }$ to −60° within an available radiation bandwidth (ARB) of 24% (i.e., 2.20–2.80 GHz) for null depth smaller than −10 dB. [ABSTRACT FROM AUTHOR]

We studied and compared the transport properties of charge carriers in bilayer graphene, monolayer graphene, and the conventional semiconductors (the two-dimensional electron gas (2DEG)). It is elucidated that the normal incidence transmission in the bilayer graphene is identical to that in the 2DEG but totally different from that in the monolayer graphene. However, resonant peaks appear in the non-normal incidence transmission profile for a high barrier in the bilayer graphene, which do not occur in the 2DEG. Furthermore, there are tunneling and forbidden regions in the transmission spectrum for each material, and the division of the two regions has been given in the work. The tunneling region covers a wide range of the incident energy for the two graphene systems, but only exists under specific conditions for the 2DEG. The counterparts of the transmission in the conductance profile are also given for the three materials, which may be used as high-performance devices based on the bilayer graphene. [ABSTRACT FROM AUTHOR]