Penn State College of Communications

About: Penn State College of Communications is a based out in . It is known for research contribution in the topics: Relay & Cognitive radio. The organization has 2106 authors who have published 2119 publications receiving 24693 citations.

Gain Enhancement for Circularly Polarized SIW Frequency Beam Scanning Antenna Using a Phase-Correcting Grating Cover

Abstract: A planar circularly polarized (CP) frequency beam scanning Fabry-Perot resonator antenna (FPRA) with enhanced gain property is presented in this paper. The antenna consists of two layers. The CP substrate integrated waveguide (SIW) beam scanning leaky-wave antenna (LWA) is used as the feeding antenna. It provides good impedance matching and stable radiation pattern over the working band. Then, partially reflecting surface (PRS) layer is introduced to improve the gain property by using a single substrate with metal patches array printed on both top and bottom surfaces. After comparisons among four patch types, circular patch type is chosen. It is an ideal choice for CP antenna because of its completely symmetrical structure along φ-plane and gentler phase slope. Parameter analysis is made for better understanding of the working principle. Finally, the antenna is fabricated and measured for verification. It shows that the main beam scans from -38° to 28° within the operating frequency band from 9.1 to 14.6 GHz (or 47.8%). The 3-dB axial ratio (AR) bandwidth is from 10.2 to 13.5 GHz (or 28.7%). Maximum gain is 14.6 dBic, and 3-dB gain bandwidth is from 11 to 14 GHz (or 26.1%). Gain enhancement of about 3.3 ~ 6 dB is achieved, compared with the unloaded type. Due to the advantages of high gain, CP beam-scanning capability, and easy fabrication, this method is a good option to design antennas in wireless communication and radar systems.

Photon-Dressed Bloch-Siegert Shift in an Ultrastrongly Coupled Circuit Quantum Electrodynamical System

Abstract: A cavity quantum electrodynamical (QED) system beyond the strong-coupling regime is expected to exhibit intriguing quantum phenomena. Here we report a direct measurement of the photon-dressed qubit transition frequencies up to four photons by harnessing the same type of state transitions in an ultrastrongly coupled circuit QED system realized by inductively coupling a superconducting flux qubit to a coplanar-waveguide resonator. This demonstrates a convincing observation of the photon-dressed Bloch-Siegert shift in the ultrastrongly coupled quantum system. Moreover, our results show that the photon-dressed Bloch-Siegert shift becomes more pronounced as the photon number increases, which is a characteristic of the quantum Rabi model.

3D CAD solid model retrieval based on region segmentation

Abstract: 3D shape retrieval may find the existing models as reference for design reuse. 3D segmentation decomposes models into new elements with large granularity and salient shapes to replace the faces in a solid model. In this way, it may reduce the complexity of a CAD model and make a local salient shape more prominent. Therefore, a retrieval method for 3D CAD solid models based on region segmentation is proposed in this paper. To deal with the problems of poor efficiency and uncertain results, a three-step segmentation method for CAD solid models is introduced. First, face adjacency graph (FAG) descriptions for query models and data models are created from their B-rep models. Second, the FAGs are segmented into a set of convex, concave and planar regions, and the relations among the regions are represented with a region graph. Finally, the sub-graphs are combined recursively to form optimal region sub-graphs with respect to an objective function through an optimal procedure. To avoid using complex graph matching or sub-graph matching for model shape comparison, region property codes are introduced to represent face regions in a CAD model. The similarity between the two compared models is evaluated by comparing their region property codes. The experiments show that the proposed method supports 3D CAD solid model retrieval.

Inclusion or Illusion? An Analysis of the FCC's Public Hearings on Media Ownership 2006–2007

Abstract: An assessment of the extent of public involvement in the FCC's media ownership hearings in 2006–07 was conducted through an analysis of the hearings' structure, the 732 public comments made in them, and the FCC's ensuing Report & Order (R&O). In light of the rising call for pluralism, direct democracy and public involvement in policy deliberations, the results reveal that the FCC consistently hindered public participation in the hearing process it initiated and managed through limited advance notice, inconvenient timing, a hearing structure that subordinated the public to experts and stakeholders, and scarce mention of public comment in the final report.

Joint spectral-temporal spectrum prediction from incomplete historical observations

Abstract: Spectrum prediction is a promising technology to infer unknown/unmeasured spectrum state from known/measured spectrum data, by exploiting the inherent correlations among them. This paper investigates spectrum prediction from a spectral-temporal two-dimensional perspective, with the primary objective to improve the prediction performance by jointly exploiting the correlations in both time and frequency domains. Moreover, a practical constraint is also considered that historical observations could be highly incomplete, due to hardware limitations and/or transmission loss. To tackle these unique challenges, we firstly study the spectral and temporal correlations in real-world spectrum measurement data. Then, we formulate the joint spectral-temporal spectrum prediction with incomplete historical observations as a matrix completion problem. To resolve this problem, a soft-impute algorithm is further introduced by leveraging the approximate low intrinsic-dimensionality of real-world spectrum data matrix. Numerical results confirm the effectiveness of the proposed scheme and demonstrate that it outperform state-of-the-art schemes.