37 results about "Band notch" patented technology

The present invention discloses an antenna for ultra-wideband (UWB) communication having a band-stop characteristic. According to an embodiment of the present invention, the UWB antenna is a patch antenna employing microstrip feeding. In order to expand a bandwidth at a low frequency band, a stub is formed in a radiating element. Furthermore, since steps are formed in a ground plane, an antenna characteristic at an intermediate frequency band can be improved and a UWB characteristic can be obtained. According to another embodiment of the present invention, the UWB antenna is a patch antenna employing microstrip feeding and has a recess formed in the ground plane, thereby implementing the UWB characteristic. The antenna of the present invention has an inverse U-shaped slot formed in the radiating element, thus implementing the band-stop characteristic at the UNII band. In addition, the antenna of the present invention has includes a ground plane having a small area and has omnidirectional radiating patterns accordingly.

An ultra wideband antenna includes: a substrate; a grounding unit, installed on the substrate and scooped with a first slot and a first strip hole; a signal feeding unit, installed on the substrate and including a horizontal portion and a vertical portion, in which the horizontal portion is located in the first slot and the vertical portion is located in the first strip hole; a first complementary, separate, circular resonator; and a second complementary, separate, circular resonator, wherein the first complementary, separate, circular resonator and the second complementary, separate, circular resonator are installed in the horizontal portion of the signal feeding unit and are connected with each other.

A photonic microwave down-conversion system and method. The oscillation loop includes an electro-optic modulator, optical narrow-band notch filter, photodetector and electrical combiner which has the function of generating the local oscillator signal. The frequency of the local oscillator signal can be flexibly adjusted by changing the lightwave frequency output from the wavelength tunable laser. The phase modulation function of the electro-optic modulator enables no RF signal output from the down-conversion photodetector It can not only down convert the RF signals with different frequencies to the intermediate frequency signals with the same frequency, but also can down convert the RF signals with the same frequency to the intermediate frequency signals with different frequencies. This can effectively overcome the limitations of complicated structure, poor RF isolation and difficulty in flexible tuning for microwave down-conversion system in the prior arts.

The invention discloses a double-notch ultra-wideband antenna, which comprises a radiation patch, a slotted floor, a feed microstrip line, a short-circuit microstrip line, a coupling patch, a WiMAX-band notch structure and a WLAN-band notch structure, wherein the radiation patch is spaced apart from the slotted floor; the feed microstrip line is spaced apart from the slotted floor; the short-circuit microstrip line is connected to the radiation patch and the slotted floor; the coupling patch is disposed in a gap of the radiation patch and the slotted floor; the WiMAX-band notch structure and the WLAN-band notch structure are both arranged on the slotted floor; the WiMAX-band notch structure uses an asymmetric U-shaped slot; and the WLAN-band notch structure uses 7-shaped and 1-shaped slots. The double-notch ultra-wideband antenna improves the peak gain of a low-frequency non-notch-band under the premise of satisfying a good notching effect of the antenna in the WiMAX band and the WLANband, thereby improving the gain stability of the antenna over the entire ultra-wide band.

The invention discloses a light-control reconfigurable ultra-wide-band notch antenna used for cognitive radio. The light-control reconfigurable ultra-wide-band notch antenna comprises an antenna radiation unit, a coplanar waveguide feeder line, an FR4 medium dielectric substrate, a symmetric trapezoidal floor, a first light-control silicon switch, a second light-control silicon switch, a third light-control silicon switch, a fourth light-control silicon switch and a fifth light-control silicon switch, the antenna radiation unit, the coplanar waveguide feeder line, the symmetric trapezoidal floor, the first light-control silicon switch, the second light-control silicon switch, the third light-control silicon switch, the fourth light-control silicon switch and the fifth light-control silicon switch are positioned on a same side of the FR4 dielectric substrate, and the coplanar waveguide feeder line is positioned in the middle of the symmetric trapezoidal floor; the antenna radiation unit comprises a U-shaped monopole antenna which is connected with the coplanar waveguide feeder line, a bent symmetric groove is formed in a U-shaped surface-mount-device monopole and is symmetric according to the coplanar waveguide feeder line in shape. The light-control reconfigurable ultra-wide-band notch antenna has the advantages of small size, high omnidirectivity, wide frequency band, small switch electromagnetic interference and the like and is suitable for the field of cognitive radio.