尔雅2020春电波传播（陈立甲）期末答案(学习通2023完整答案)

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01 Introduction

简答题

1、尔雅你认为提高工作频率对通信和雷达系统分别有什么好处？试简要说明。春电

02 Basic The波传播陈ory part I

第二次作业

1、P2.6. Plane radio wave of the frequency 300 MHz penetrates into homogeneous see water (ε = 80,立甲 σ = 1 Sim/m) along Z-axes. The effective field strength at the excitation point (point of origin) is 0.1 V/m. What is the maximum expected propagation distance if the least detectable value of the field strength (receiver's threshold) is equal 1 μV/m ?

02 Basic Theory part II

第三次作业

1、计算题，期末参见附件内容。答案

02 Basic The学习ory part III

第四次作业

1、P3.9. A geostationary satellite broadcasts direct TV program at the frequency 12 GHz. The通完 onboard antenna has EIRP = 70 dB / W. Estimate approximate area of effective aperture of the receiving ground dish antenna without taking into account additional losses such as polarization loss, atmospheric absorptions, etc. Take the distance from earth to satellite equal 36000 km, and the receiver's input power -90 dB / W.

04 Atmospheric Effects on Radio Wave Propagation II

第五次作业

1、P4.2. An omnidirectional FM broadcast antenna of horizontal polarization,整答 at the height h1= 80 m has a gain of GTx = 5 (unitless) at the frequency f = 100 MHz. Calculate the field strength of the radio wave for the following distances, if the receiving antenna is placed at the height h2 = 10 m, and the transmitter's output power is PTx = 500 W: (1) r = 1 km, (2) r =6 km, (3) r = 25 km. Note: 1). Consider the propagation over the dry soil ( ε = 3, σ = 10-4 S/m), without any roughness on ground surface