The purpose of this paper is to introduce a compact Ultra-Wideband (UWB) diversity antenna with a very low Envelope Correlation Coefficient (ECC). The design employs a hybrid isolation enhancing and miniaturization technique. The antenna consists of two counter facing monopoles, and is miniaturized by using not only inverted-L stubs but also a Complementary Split Ring Resonator (CSRR) on the ground plane. The added components enhance isolation and enable tighter packing of the antennas. The result is a very compact MIMO array with an overall size of 23 x 29 mm2, that covers the entire UWB spectrum from 3 GHz to 12 GHz, with mutual coupling lower than-15 dB. Moreover, the CSRR unit that acts as a resonator is applied for the first time to suppress the interference of RF currents flowing through the ground plane of this UWB MIMO/diversity antenna. The performance of the fabricated prototype in terms of scattering parameters, broadside (peak) gain, radiation patterns, efficiency and envelope correlation coefficient is presented and discussed

A compact planar UWB-MIMO antenna array with WLAN band rejection is presented. The array consists of four monopole radiators and a common ground plane. These monopoles are placed in such a way that the polarisation diversity of nearly placed radiators is exploited, resulting in high isolation. The proposed MIMO antenna array is electrically small (50 × 39.8 mm 2), printed on a low loss 1.524 mm thick Rogers TMM4 laminate with a dielectric constant of 4.5 and a loss tangent of 0.002. A band-stop design was inserted on the ground plane to behave similar to a LC band-stop filter and reject the WLAN band. Simulation and measurement results satisfy the return loss requirement of better than 10 dB and isolation better than 17 dB over the entire 2.7-5.1 and 5.9-12 GHz bandwidths.

We introduce a simple approach for the efficient generation of tunable narrow-bandwidth picosecond pulses synchronized to broadband femtosecond ones. Second harmonic generation in the presence of large group velocity mismatch between the interacting pulses transfers a large fraction of the energy of a broadband fundamental frequency pulse into a narrowband second harmonic one. Using a periodically poled stoichiometric lithium tantalate crystal coupled to an infrared optical parametric amplifier, we generated 200-nJ pulses with spectral width lower than 8.5 cm(-1) and tunability from 720 to 890 nm. Energy scaling and extension of the tuning range are straightforward.

The system design of an integrated microwave imaging radar for the diagnostic screening of breasts cancer is presented. A custom integrated circuit implemented in a 65-nm CMOS technology and a pair of patch antennas realized on a planar laminate are proposed as the basic module of the imaging antenna array. The radar operates on the broad frequency range from 2 to 16 GHz with a dynamic range of 107 dB. Imaging experiments carried out on a realistic breast phantom show that the system is capable of detecting tumor targets with a resolution of 3 mm