微波EDA网,见证研发工程师的成长!
首页 > 研发问答 > 微波和射频技术 > 天线设计和射频技术 > Little COnfusion about Antennas,Monopole Antenna

Little COnfusion about Antennas,Monopole Antenna

时间:04-06 整理:3721RD 点击:
Hello friends,i was reading about monopole Antennas, most popular monopole antenna's are Whip Antenna,which are mounted on Cars for its radio receivers...
I read, monopole Antenna will have a GROUND PLANE, here my doubt arises...

Imagine i have a transmitter circuit and i want to use the monopole Antenna with my transmitter,i will connect the out put from the collector of last stage transistor through a capacitor to the monopole Antenna, and i was thinking should the ground plane should be connected to the NEGATIVE point of the transmitters power source?


Or else the ground plane should not be connected to transmitter and should not be connected to the Antenna too but it has to be placed under the antenna where the Antenna stand perpendicularly to the ground plane to work as a Signal reflector?


Plz help me understand this..

The antenna ground plane will ideally be connected to the ground on the last active device in the transmitter, or the first active device in the receiver, chain. So if you have a transmitter with a power fet at the last stage, the source of the FET is attached with low inductance/resistance to the antenna ground plane.

Alternatively, you can hook the transmitter to a coaxial cable, and the coaxial cable has the center contact go to the monopole whip, and the ground shield go to the ground plane.

If you assume the negative is a good ground point, you are ignoring the various wire inductances and resistances in series.

Glad that i got some help

And I didn't understand that highlighted sentence,Wat does the Source of the FET mean?

The schematic uses a NPN transistor,so the source of the NPN is attached with low inductance/resistance to the antenna ground plane.

Is it the signal source of the NPN transistor or the Power source of the NPN?or i should connect it to the negative source of the circuit?

To make my question easier,ill post this Random sample schematic,the monopole antenna is connected to the collector through a 100p cap,And can you please point out where the ground plane should be connected?

Connect the ground plane to the circuit ground. Somewhere near the emitter of T4.

Ty for your help biff and volker,i'll try it and if i don't encounter and problem ill mark the thread a solved

上一篇:Class AB reference design
下一篇:最后一页

Copyright © 2017-2020 微波EDA网 版权所有

网站地图

Top