The following functions need to be performed by the active antenna:
This function is performed by the short rod antenna.
This function is performed by the amplifier.
This function will be performed by passive filters at both ends of the cable.
The design of the antenna and the design of the power splitter/combiner are not part of this design exercise.
The antenna will have a length of 50cm and a diameter of 5mm. The convergion gain from E-field to open-circuit output voltage equals its length.
The source capacitance of this antenna over the frequency range of interest is about 6.3pF.
The amplifier will be supplied from a low-noise supply source that is connected to the amplifier with a separate cable.
The performance specifications of the coplete signal chain that consists of the antenna, the amplifier and the cable terminated with 50$\Omega$ are given below.
The antenna capacitance $C_A$ [F] equals:
\begin{equation} C_{A}=6.3 \cdot 10^{-12} \end{equation}The antenna conversion gain $G_A$ [m] equals:
\begin{equation} G_{A}=0.5 \end{equation}The gain of the active antenna $G_{AA}$ in [m] is defined as the gain from the E field at the input of the antenna to the voltage across the 50 $\Omega$ termination of the cable:
\begin{equation} G_{AA}=0.5 \end{equation}The maximum value of the RMS field strength at the antenna [V/m] equals:
\begin{equation} E_{A}=0.45 \end{equation}The crest factor is not specified. Hence is it not possible to determine the peak-to-peak value of the E-field.
A gain compression of 1dB is allowed at a single-frequency output signal level $V_{o1dB}$ [V] of 0dBm (225mV RMS).
\begin{equation} V_{o 1dB}=0.225 \end{equation}The (-3dB) frequency range of interest ranges from $f_l$ to $f_h$ [Hz], where:
\begin{equation} f_{l}=1.0 \cdot 10^{4} \end{equation} \begin{equation} f_{h}=3.0 \cdot 10^{7} \end{equation}The maximum inaccuracy $\delta_{GAAmax}$ [-] of the gain at midband frequencies $f_{mbl}$ to $f_{mbf}$ [Hz] should be:
\begin{equation} \delta_{G AA max}=0.2 \end{equation} \begin{equation} f_{mbl}=1.0 \cdot 10^{5} \end{equation} \begin{equation} f_{mbh}=1.0 \cdot 10^{6} \end{equation}The antenna-referred (E-field) noise in [V^2/m/Hz] over the frequency range of interest should be less then:
\begin{equation} S_{E}=9.5 \cdot 10^{-17} + \frac{3.0 \cdot 10^{-6}}{f^{2}} \end{equation}The load of the active antenna is a 50$\Omega$ cable terminated with 50$\Omega$. This cable should be driven from its charactersitic impedance.
Hence, the output impedance $Z_o$ [$\Omega$] of the amplifier must equal its load impedance $Z_l$ [$\Omega$] :
\begin{equation} Z_{l}=50 \end{equation} \begin{equation} Z_{o}=50 \end{equation}Temperature range and ESD conditions are mentioned in the application description.
The operating temperature ranges from $T_{man}$ to $T_{max}$ [C], where:
\begin{equation} T_{min}=-25 \end{equation} \begin{equation} T_{max}=70 \end{equation}The ESD conditions have not been specified.
The width $PCB_W$ [mm], the length $PCB_L$ [mm] and the heifht $PCB_H$ [mm] of the PCB should maximally be:
\begin{equation} PCB_{W}=25 \end{equation} \begin{equation} PCB_{L}=50 \end{equation} \begin{equation} PCB_{H}=15 \end{equation}The maximum supply voltage $V_{supplyMax}$ [V] should be:
\begin{equation} V_{supply Max}=10 \end{equation}The maximum power taken from the sullpy $P_{supplyMax}$ [W] should be:
\begin{equation} P_{supply Max}=0.25 \end{equation}Go to index
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Last project update: 2021-02-22 16:37:10