March 27, 2017

Dielectric powder loaded coaxial-cavity filters

  • Bulja S.
  • Doumanis E.
  • Pivit F.

In this paper we demonstrate the use of low-loss powders in the design and fabrication of RF filters. Initially, several different powders are tested for their RF performance - in particular their relative dielectric permittivity and loss tangent. Then, based on the information obtained in this way, the best performance powder is used to design a 5 pole Chebyshev filter operating at a centre frequency of 779 MHz, with a bandwidth of 17 MHz. Upon fabrication of the filter housing, the filter cavities are filled with the powder. Compaction of the powders is achieved in a systematic way and has resulted in stable performance.

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Recent Publications

June 04, 2017

A New PRACH Transmission Scheme in Unlicensed Spectrum

  • Luo Z.
  • Meng Y.
  • Tao T.

For the unlicensed spectrum, the occupied bandwidth requirement is demanded by some regulations. The legacy scheme of Physical Random Access Channel (PRACH) for Long Term Evolution (LTE) cannot satisfy it. In this paper, we propose a novel PRACH transmission scheme to satisfy the requirement of unlicensed spectrum based on preamble ...

June 01, 2017

Mutual service processes in Euclidean spaces: existence and ergodicity

  • Baccelli F.
  • Mathieu F.
  • Norros I.

Consider a set of objects, abstracted to points of a spatially stationary point process in R-d, that deliver to each other a service at a rate depending on their distance. Assume that the points arrive as a Poisson process and leave when their service requirements have been fulfilled. We show ...

June 01, 2017

Incentivizing social media users for mobile crowdsourcing

  • Aiello L.
  • Karaliopoulos M.
  • Koutsopoulos I.
  • Micholia P.
  • Morales G.
  • Quercia D.

We focus on the problem of contributor-task matching in mobile crowd-sourcing. The idea is to identify existing social media users who possess domain expertise (e.g., photography) and incentivize them to perform some tasks (e.g., take quality pictures). To this end, we propose a framework that extracts the potential contributors' expertise ...