Isotropic negative permeability resulting from Mie resonance is demonstrated in a three-dimensional (3D) dielectric composite consisting of an array of dielectric cubes. A strong subwavelength magnetic resonance, corresponding to the first Mie resonance, was excited in dielectric cubes by electromagnetic wave. Negative permeability is verified in the magnetic resonance area via microwave measurement and the dispersion properties. The resonance relies on the size and permittivity of the cubes. It is promising for construction of novel isotropic 3D left-handed materials with a simple structure.

Articles you may be interested inEquivalent circuit model of an ultra-thin polarization-independent triple band metamaterial absorber AIP Advances 4, 097127 (2014); 10.1063/1.4896282 Adjustable low frequency and broadband metamaterial absorber based on magnetic rubber plate and cross resonator J. Appl. Phys. 115, 064902 (2014); 10.1063/1.4863540 Towards left-handed metamaterials using single-size dielectric resonators: The case of TiO2-disks at millimeter wavelengths Appl. Phys. Lett. 101, 042909 (2012); 10.1063/1.4739498 Achieving all-dielectric left-handed metamaterials via single-sized dielectric resonators J. Appl. Phys. 111, 044903 (2012); 10.1063/1.3686200 Metamaterial exhibiting left-handed properties over multiple frequency bandsIn this paper, we propose and fabricate multiband all-dielectric left-handed metamaterials (ADMs) in the X-band microwave regime. The ADMs are fabricated by a combination of dielectric resonators in shapes of cubes and rods. The ADMs can exhibit two left-handed pass bands while the rods contact the sidewalls of the waveguide. A band split phenomenon is observed when the boundary conditions of dielectric rods change. The two pass bands can diverge into three left-handed pass bands when the rods do not contact the waveguide. By using field analysis and dielectric resonator theory, we prove that the boundary conditions have a strong influence on the resonant modes of the rod resonator, which plays key roles in left-handedness. The boundary tuned resonant modes can broaden our ways of designing new types of metamaterials. V C 2014 AIP Publishing LLC. [http://dx.

To address the problem of a serious Internet of Things (IoT) talent shortage, the Chinese government is encouraging universities and institutions to establish a major in IoT Engineering to train high-level IoT talent. Since 2011, 700 Chinese universities and institutions have established IoT Engineering undergraduate programs. We surveyed the history, status, curriculum, and problems of IoT undergraduate degree programs in China. Based on data collected from faculties, students, and graduates, we found that the IoT Engineering curriculum was an unsystematic patchwork and was deficient in practical platforms. We then provide suggestions for further development and exploration of IoT education by presenting a Technical Knowledge Map of IoT Engineering. This survey work on Chinese IoT education can prompt Chinese educators to reflect on its achievements and problems, which will contribute to IoT talent cultivation worldwide.

We demonstrate that using single-sized dielectric resonators, all-dielectric left-handed metamaterial (LHM) can be achieved in the C-band microwave regime. The single-sized rectangular resonator, operating under higher-order resonant modes, possesses electric and magnetic responses simultaneously, leading to the double-negative resonance behavior. We find that the electric/magnetic resonance can be enhanced by elongating the size of the rectangular resonators along the electric field direction. It is shown that polarization currents in dielectric resonators are the same as conduction currents in cut-wire pairs. Experiments were carried out to verify the designed all-dielectric LHM. The proposed method provides a convenient route to all-dielectric LHMs.

In this paper, we develop a joint design method of network-channel Low Density Parity Check codes (LDPC) codes by constructing joint network-channel parity check matrix. Random network coding is performed to provide side information for both the Source and Relay s transmission. This system matrix makes an easy way to collect all independent signal copies to provide a spatial diversity gain. And the complexity of network coding is linear to the block length ~O(n) Then, the optimization of joint network-channel LDPC code is conducted in term of maximizing the system rate. Based on the joint networkchannel LDPC codes, we presents a protocol for wireless cooperative communications, which is very effective to combat the channel fading without much rise in system bandwidth and transmitting power. A traditional three-node model is built to describe the protocol where relay not only helps source to transmit but also has its own information to transmit.