51results about How to "Broaden the bandwidth of the frequency band" patented technology

A wireless cellular communication system in which groups of cellular base stations communicate with a central office via a narrow-band millimeter wave trunk line. The transceivers are equipped with antennas providing beam divergence small enough to ensure efficient spatial and directional partitioning of the data channels so that an almost unlimited number of transceivers will be able to simultaneously use the same millimeter wave spectrum. In a preferred embodiment the trunk line communication link operates within the 92 to 95 GHz portion of the millimeter spectrum. A large number of base stations are each allocated a few MHz portion of a 900 MHz bandwidth of the millimeter wave trunk line. A first transceiver transmits at a first bandwidth and receives at a second bandwidth both within the above spectral range. A second transceiver transmits at the second bandwidth and receives at the first bandwidth. Antennas are described to maintain beam directional stability to less than one-half the half-power beam width. In a preferred embodiment the first and second spectral ranges are 92.3–93.2 GHz and 94.1–95.0 GHz and the half power beam width is about 0.36 degrees or less. Thus, in this system the low frequency band width is efficiently utilized over and over again by dividing a territory into small cells and using low power antenna. And a higher frequency bandwidth is efficiently utilized over and over again by using transmitting antennae that are designed to produce very narrow beams directed at receiving antennae. In a preferred embodiment cellular base stations are prepackaged for easy quick installation at convenient locations such as the tops of commercial buildings.

The invention discloses an orthotropic piezoelectric sensor for monitoring / detection of a civil engineering structure. The orthotropic piezoelectric sensor for monitoring / detection of the civil engineering structure comprises an orthotropic piezoelectric composite material component, a matching layer, a back-lining layer and a wire, wherein the lower surface of the orthotropic piezoelectric composite material component is connected with the matching layer, other surfaces of the orthotropic piezoelectric composite material component are connected with the back-lining layer, the surface of the matching layer and the surface of the back-lining layer are respectively provided with a shielding layer in a coating mode, and the wire is respectively connected with a positive electrode and a negative electrode of the orthotropic piezoelectric composite material component. The invention further discloses a preparation method of the orthotropic piezoelectric sensor for monitoring / detection of the civil engineering structure, and application of the orthotropic piezoelectric sensor for monitoring / detection of the civil engineering structure. The orthotropic piezoelectric sensor for monitoring / detection of the civil engineering structure has the advantages of being obvious in orthotropic characteristic, good in sensitivity, wide in response frequency band, good in disturbance-resisting capacity, capable of having different response characteristics aiming at different directions, and capable of effectively restraining reception of sidewise interference signals, and improving a signal-to-noise ratio.