A well-designed reflector surface with high beam pointing accuracy in electromagnetic performance is of practical significance to the space application of cable mesh reflector antennas. As for space requirements, cir-...A well-designed reflector surface with high beam pointing accuracy in electromagnetic performance is of practical significance to the space application of cable mesh reflector antennas. As for space requirements, cir- cular polarizations are widely used in spaceborne antennas, which usually lead to a beam shift for offset reflectors and influence the beam pointing accuracy. A two-step structural design procedure is proposed to overcome the beam squint phenomenon for high beam pointing accuracy design of circularly polarized offset cable mesh reflectors. A simple structural optimal design and an integrated structural electromagnetic optimization are combined to alleviate the beam squint effect of circular polarizations. It is imple- mented by cable pretension design and adjustment to shape the offset cable mesh surface. Besides, in order to increase the efficiency of integrated optimization, an update Broy- den-Fletcher-Goldfarb-Shanno （BFGS） Hessian matrix is employed in the optimization iteration with sequential quadratic programming. A circularly polarized offset cable mesh reflector is utilized to show the feasibility and effectiveness of the proposed procedure. A high beam pointing accuracy in order of 0.0001~ of electromagnetic performance is achieved.展开更多
在Wimax(IEEE802.16)Mesh网络集中调度机制中,通常采用树形拓扑,由于数据都是往来于Mesh基站(MBS,Mesh Base Station)的,越靠近MBS的节点,需要中继的数据越多,因此越可能成为影响网络吞吐量的瓶颈节点。当采用全向天线时,使用各种先进...在Wimax(IEEE802.16)Mesh网络集中调度机制中,通常采用树形拓扑,由于数据都是往来于Mesh基站(MBS,Mesh Base Station)的,越靠近MBS的节点,需要中继的数据越多,因此越可能成为影响网络吞吐量的瓶颈节点。当采用全向天线时,使用各种先进的调度算法都不能有效解决这个瓶颈问题。提出了在网络节点上(尤其是在瓶颈节点上)使用多波束智能天线,使更多链路可以并行传输,从而有效解决瓶颈问题。仿真结果表明,提出的方法可以显著提高网络吞吐量,而且,仅在瓶颈节点上使用多波束智能天线,可以在性能与代价之间进行折中。展开更多
The performances of two microstrip patch antennas with low visual impact are presented in this paper and compared to an opaque solution. These consist in a copper film deposited on a Borofloat 33 glass substrate throu...The performances of two microstrip patch antennas with low visual impact are presented in this paper and compared to an opaque solution. These consist in a copper film deposited on a Borofloat 33 glass substrate through a thin titanium gripping layer. The mesh is obtained by wet chemical etching. Antennas differ by the dimensions in the ground plane mesh pattern. The opaque antenna only consists of a full copper deposit. The transparency work was mainly carried out on the ground plane as it is the largest area available. Specific attention is paid to optical transparency in the visible light spectrum, sheet resistance and electromagnetic performances in the [2.8;3 GHz] bandwidth. They are measured in each case, compared and discussed. Both simulations and measurement results show good performance, especially the antenna with the most transparent ground plane: a high level of optical transparency of almost 73%, coupled with a sheet resistance of less than 0.028 Ohms/sq and a gain of about 3.22 dBi at 2.8 GHz, slightly higher than the gain of the reference opaque antenna of about 2.66 dBi at 2.99 GHz. The opaque reference antenna has a bandwidth of 1.30 GHz while those of the transparent antennas are about 1.60 GHz and 2.10 GHz (S<sub>11</sub> < −10 dB). This solution presents a real interest for low cost integrated and discrete antenna solutions in ISM band.展开更多
文摘A well-designed reflector surface with high beam pointing accuracy in electromagnetic performance is of practical significance to the space application of cable mesh reflector antennas. As for space requirements, cir- cular polarizations are widely used in spaceborne antennas, which usually lead to a beam shift for offset reflectors and influence the beam pointing accuracy. A two-step structural design procedure is proposed to overcome the beam squint phenomenon for high beam pointing accuracy design of circularly polarized offset cable mesh reflectors. A simple structural optimal design and an integrated structural electromagnetic optimization are combined to alleviate the beam squint effect of circular polarizations. It is imple- mented by cable pretension design and adjustment to shape the offset cable mesh surface. Besides, in order to increase the efficiency of integrated optimization, an update Broy- den-Fletcher-Goldfarb-Shanno （BFGS） Hessian matrix is employed in the optimization iteration with sequential quadratic programming. A circularly polarized offset cable mesh reflector is utilized to show the feasibility and effectiveness of the proposed procedure. A high beam pointing accuracy in order of 0.0001~ of electromagnetic performance is achieved.
文摘在Wimax(IEEE802.16)Mesh网络集中调度机制中,通常采用树形拓扑,由于数据都是往来于Mesh基站(MBS,Mesh Base Station)的,越靠近MBS的节点,需要中继的数据越多,因此越可能成为影响网络吞吐量的瓶颈节点。当采用全向天线时,使用各种先进的调度算法都不能有效解决这个瓶颈问题。提出了在网络节点上(尤其是在瓶颈节点上)使用多波束智能天线,使更多链路可以并行传输,从而有效解决瓶颈问题。仿真结果表明,提出的方法可以显著提高网络吞吐量,而且,仅在瓶颈节点上使用多波束智能天线,可以在性能与代价之间进行折中。
文摘The performances of two microstrip patch antennas with low visual impact are presented in this paper and compared to an opaque solution. These consist in a copper film deposited on a Borofloat 33 glass substrate through a thin titanium gripping layer. The mesh is obtained by wet chemical etching. Antennas differ by the dimensions in the ground plane mesh pattern. The opaque antenna only consists of a full copper deposit. The transparency work was mainly carried out on the ground plane as it is the largest area available. Specific attention is paid to optical transparency in the visible light spectrum, sheet resistance and electromagnetic performances in the [2.8;3 GHz] bandwidth. They are measured in each case, compared and discussed. Both simulations and measurement results show good performance, especially the antenna with the most transparent ground plane: a high level of optical transparency of almost 73%, coupled with a sheet resistance of less than 0.028 Ohms/sq and a gain of about 3.22 dBi at 2.8 GHz, slightly higher than the gain of the reference opaque antenna of about 2.66 dBi at 2.99 GHz. The opaque reference antenna has a bandwidth of 1.30 GHz while those of the transparent antennas are about 1.60 GHz and 2.10 GHz (S<sub>11</sub> < −10 dB). This solution presents a real interest for low cost integrated and discrete antenna solutions in ISM band.
