Trial Manufacture of Diversity Antennas Utilizing Multibeam Arrays

诸如移动的电话和个人手持电话的无线通信系统将被引入到现代通信网络中。为了实现这一点，必须建立避免由于多径传播引起的衰落的技术。本研究提出多波束阵列天线作为分集接收天线的应用，并通过试制和传播实验对其性能进行评估。4-在1.5GHz频段上制作了矩形和圆形微带贴片天线的8单元阵列，并对其辐射方向图进行了评价。BFN采用Butler矩阵网络，8个单元的阵列在平面上二维排列，阵列为正六边形加1个单元的形状。这是世界上第一个成功制造的平面多波束阵列。实测辐射场与理论计算结果相吻合，各波束间的正交性良好。在一个面积为6.9 × 8.7[m]的房间内进行了传播实验，其中准备了4种环境，即（a）朝向发射天线的空间是自由的或（B）被阻挡，以及（c）窗户处的百叶窗是电磁波的良好反射器，被拉下或（d）被拉上。通过8个分支，在10%累积分布下观察到的分集增益为7.03 dB。数值模拟估计，在1%的累积分布是15.78 dB的4个分支，和19.81 dB的8个分支。随后，采用一种新的测量设备，在2.5GHz频段对一个具有孔径耦合和圆极化的3单元圆形贴片天线平面阵列进行了测试，其中采用了改进的Blass网络作为BFN，在1%累积分布下的分集增益估计约为13dB，与数值模拟结果吻合较好。

Wireless communication systems such as mobile telephones and personal handy phones are going to be introduced in date communication networks. For this realization, techniques avoiding fading due to multipath propagation have to be established. This research proposes the application of multibeam array antennas as antennas of diversity reception, and evaluates their performance by conducting trial manufacture and propagation experiment. 4-and 8 elements arrays of rectangular or circular microstrip patch antennas are fabricated at the frequency band of 1.5 GHz, and the radiation pattems are evaluated. Butler matrix networks are utilized as the BFN.The array of 8 elements are arranged on a plane two-dimensionally, with the array being a regular hexagon plus 1 element shape. This is the first successfully manufactured planar multibeam array in the world. The measured radiation pattems coincide with the theory, and the orthogonality between every beams are good. The propagation experiment have been conducted inside a room with 6.9 * 8.7[m] area, where 4 kinds of environment are prepared, i.e. (a) the space looking the transmitting antenna is free or (b) obstructed, and (c) the shutter at the windows which is good reflectors of electromagnetic waves are pulled down or (d) up. The observed diversity gain at 10% cumulative distribution was 7.03 dB by 8 branches. The numerical simulation estimates one at 1% cumulative distribution to be 15.78 dB by 4 branches, and 19.81 dB by 8 branches. Later, a new measuring equipment with higher accuracy was introduced, and a planar array of 3 elements circular patch antennas with aperture coupling and circular polarization was tested at 2.5 GHz band, where a modified Blass network was utilized as the BFN.The diversity gain in this case for 1% cumulative distribution was estimated to be about 13 dB,which was in good agreement with the numerical simulation.