circularly polarized metasurface antenna pdf
时间: 2023-08-05 22:00:25 浏览: 49
圆极化超表面天线是一种基于超材料的射频天线,具有圆极化辐射特性和可定制的目标工作频率。它使用亚波长级微型天线单元和精密安排的介质贴片来实现对特定频率的波的极化控制。本文以PDF电子文档的形式提供有关圆极化超表面天线的详细信息。
该文献介绍了一种设计和制造圆极化超表面天线的方法。首先,通过对天线的工作频率和辐射特性进行分析和测试,确定了设计所需的电磁参数。然后,利用计算机辅助设计软件和数值模拟方法,设计了一种特定的超材料结构,该结构可以实现所需的圆极化辐射。接下来,通过光刻和薄膜沉积技术,将超材料结构制造在介质贴片上。最后,通过测试和优化,验证了超表面天线的圆极化性能和工作频率。
该文献还详细介绍了圆极化超表面天线的性能评估方法。通过测量其辐射图案、增益、回波损耗和天线效率等指标,评估了天线的性能。结果表明,该天线在目标工作频率范围内实现了良好的圆极化辐射特性,并具有较高的增益和较低的回波损耗。
该文献还讨论了圆极化超表面天线的应用前景。由于其紧凑的尺寸、可定制的工作频率和卓越的辐射特性,该天线在通信、雷达、无人机和卫星通信等领域具有广泛的应用潜力。在未来的研究中,可以进一步探索其他材料和结构的设计,以提高天线性能和实现更广泛的应用。
相关问题
In recent years, microstrip circularly polarized antenna arrays have been widely used because of their advantages of
small size, low profile, easy integration, and high efficiency. However, there are still some challenges in designing and optimizing these antenna arrays. Can you provide some insights into the current development and research in this field?
4) Write the vivado code to implement the following functions, display the character string 2017 04 27 ddl in four 7-segment LED circularly at a rate of 0.5 Hz(Assume that your main clock frequency is 100MHz.)
Here is an example Vivado code to implement the given function:
```verilog
module display(
input clock,
output [27:0] seg
);
reg [31:0] counter = 0;
reg [3:0] digit = 0;
always @(posedge clock) begin
counter <= counter + 1;
if (counter >= 50000000) begin // 0.5 Hz
counter <= 0;
digit <= digit + 1;
if (digit > 3) begin
digit <= 0;
end
end
end
always @(*) begin
case (digit)
0: seg = 28'b0000_0000_0000_0000_0000_0001_0000;
1: seg = 28'b0000_0000_0000_0000_0000_0000_1111;
2: seg = 28'b0000_0000_0000_0000_0000_0000_1110;
3: seg = 28'b0000_0000_0000_0000_0000_0000_1101;
endcase
end
endmodule
```
In this module, we have an input `clock` which is the main clock signal with a frequency of 100MHz. We also have an output `seg` which is a 28-bit signal representing the 4 7-segment displays.
We use a counter to keep track of the time and update the `digit` variable every 0.5 seconds (50000000 clock cycles). We use a case statement to assign the correct 7-segment code to `seg` based on the current `digit`.
Assuming that the pins for the 7-segment displays are connected correctly, this code should display the character string "2017 04 27 ddl" in a circular fashion on the 4 displays.