# P波段高增益圆极化天线

(1. 电子科技大学清水河校区，611731)

P-Band High-Gain Circularly Polarized Antenna
Ran Chunlin Ma Yuemin1
(1. Sichuan Chengdu, University of Electronic Science and Technology 611731）

Abstract：This is designed to use the knowledge learned in Antenna Principles and Design to analyze the radiation principle of the axial mode helical antenna, design a double-arm tapered helical antenna, and give the design model and preliminary simulation results; at the operating frequency of 700MHz Achieve the set goals of S11<-10dB, VSWR<2, G≥12dB.
Key words：High-gain; circular polarization; helical antenna

# 平行耦合线带通滤波器设计

(1. 电子科技大学清水河校区，611731)

## 1 低通原型滤波器[1]

2.4GHz2.3~2.5GHz<0.15dB>25dB(f>2.8GHz)>25dB(f<2.0GHz)

$$L_{A}\left( \omega^{'} \right) = 10{\log\left\lbrack 1 + \varepsilon T_{n}^{2}\left( \omega^{'} \right) \right\rbrack}$$

$$T_{n}^{2}\left( \omega^{'} \right) = \left\{ \begin{matrix} {{cos}^{2}\left\{ {narccos\omega^{'}} \right.,~~~\omega^{'} \leq 1} \\ {{ch}^{2}\left\{ {narch\omega^{'}} \right.,~~~~~~~~~\omega^{'} \geq 1} \\ \end{matrix} \right.$$

$$\varepsilon = 10^{\frac{L_{Ar}}{10}} - 1$$

# 一种平衡式镜像回收混频器分析

Error:此图混频器A有错误，应旋转90度使输入信号和二极管之间为低阻抗线

两个混频器用圆弧形功分器相连，射频信号$f_S$和本振信号$f_L$等相位等分地加载到两个平衡混频器上，混频器的周长为$\lambda_g$，$D_1 \sim D_4$为二极管，其余各参数见标注。图中给出了当$\omega_S > \omega_L$时中频移相器的位置，试分析当$\omega_S < \omega_L$时，中频移相器的位置应在何处？

# 低噪声放大器设计

## 0 题目

$$\begin{cases} S_{11}=0.9\angle-90^\circ \\ S_{12}=0 \\ S_{21}=2\angle 90^\circ \\ S_{22}=0.5\angle-45^\circ \end{cases}$$

$$\begin{cases} \Gamma_{opt}=0.5\angle135^\circ \\ F_{min}=3dB \\ R_N=4\Omega \end{cases}$$

1. 拥有最小噪声系数的总增益
2. 设计放大器电路的输入、输出匹配网络
3. 绘制具体电路图，详述设计过程
4. 若输入信号为$-20dB$，分别对理想无噪声信号和噪声温度为$100K$时，计算放大器输出功率和输出噪声
5. 当输入噪声温度为$100K$时，计算输入信噪比与输出信噪比的比值
6. 利用公式计算微带线有效介电常数$\varepsilon_e$、$Z_0$，微带线金属导体厚度$t=35\mu m$