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An on-chip continuous-variable quantum key distribution(CV-QKD) system is integrated using silicon photonics fabrication process and demonstrates the capability of transceiving Gaussian-modulated coherent states and homodyne detection.

Abstract-This paper presents a novel modified composite right/lefthanded (CRLH) unit cell to achieve sharp rejection at 5.8 GHz. Design formulas are theoretically derived and numerically verified. Based on this unit cell, ultra-wideband (UWB) bandpass filters with two and three cells are designed, fabricated, and on-wafer measured. The measurement results show that the CRLH bandpass filter has a rejection of > 60 dB at 5.8 GHz, a minimum insertion loss of 1.1 dB, and 3-dB bandwidths of 3.09-4.79 GHz and 3.22-4.61 GHz for the two and three unit cells, respectively.

A novel design of circularly polarized square slot antenna fed by a coplanar waveguide for lower ultra‐wideband (UWB) application is presented. Circular polarization is achieved by protruding a truncated corner and a grounded inverted‐L strip at two opposite corners, respectively. The antenna is investigated both in the frequency and time domains. The results show that its measured 10‐dB return loss bandwidth is from 2.7–5.0 GHz and 3‐dB axial ratio bandwidth varies from 3.5 to 4.8 GHz, whereas the size is just 35 mm × 35 mm. The proposed antenna is suitable for lower UWB system (3.4–4.8 GHz) applications in Singapore. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2365–2369, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24629