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Questions tagged [antenna]

Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g. TV or radio) waves. -Wikipedia

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Long range, medium speed RF data transmission?

I'd like to stream an audio signal, roughly real-time, with a data rate of at least 256kbps. The RF link should be bidirectional to allow for control signals, however if necessary it may be heavily ...
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1answer
31 views

Knife-Edge Diffraction:Hight of the top of the obstacle above the straight line

I found this picture here. If h>0, does it mean that ''view free'' and h<0 - shadow? edit 1: What is " obstacle gain"? I found only that it is equal to 2*h/r (fresnel), and no explanation
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30 views

Troposcatter: size of signal beam

I actually have big doubts. How I know power decrease with distance. According to the radiation pattern of the antenna, I can conclude that in the " end" of the distance the size of the main lob will ...
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23 views

coaxial balun: Z=4R?

My quastion is according to half-wavelength coaxial balun 1:4. Why does the input current split into two equal parts (twice larger voltage and twice smaller current )?
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35 views

Patch antennas: explanation of examples

I am studying patch antennas for mobile communication (technology.) I have found some examples of them but without explanation. Maybe can someone explain to me the difference of examples from this ...
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44 views

Layout questions on RF design based around vendor patch antenna

I'm struggling with a basic antenna design around a 868 MHz patch antenna. The datasheet of the vendor is particularly sparse in regards of layout guidelines. A rough preliminary sketch of the layout ...
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29 views

Antenna selection for CC1101-433 MHz rf

I intend to use these TI CC1101 433 MHz RF modules in one of my project: Wavelength of 433 MHz will be 69 cm. Half wavelength will be 34.5 cm. Vendor is selling two antenna options with the product. ...
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28 views

Suitable antenna for XBee S3 PRO 900hp working at 900MHz frequency

We are currently working on a project using 3 XBee modules. One is like a data center or the master of the other two XBees. We did a range test with a master and a slave XBee on an open field using a ...
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2answers
44 views

Impact of PCB thickness to an antenna design

I have an independent PCB design for a standard SMT-placed antenna. There are large ground planes on both side. I can understand that the thickness is going to change the values of the matching ...
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Adding position markers in HFSS

I need to add a position marker in HFSS something like a point or square so that I can draw a line between two points with a certain length. So it is possible to do so in HFSS ?
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42 views

Linear antenna: with electromagnetic coil, trap circuit

I am trying to understand the concept of the linear antennas. I have read that the linear antennas are the simplest form of the antenna in the case of asymmetrical (coaxial) feed. what happens if I ...
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1answer
233 views

UHF RFID: Why are read range (forward) and backscatter range curves different?

I have made two measurements with a UHF RFID tag (pic below) My test setup consists of a reading device with a sensitivity of -70dBm and an antenna gain of 6dBi. I made a frequency sweep across 700 - ...
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Can antennas be viewed as light sources?

Clearly antennas are nothing but a device to radiate the electrical energy through electromagnetic waves. Since visible light is also simply a certain range of frequencies, isn't it more easier to ...
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1answer
93 views

Ability of a 100km power transmission line to radiate 50Hz EM waves?

This is about confusion of relating antenna radiation theory to power lines. Assuming a straight 100km or even longer possible power transmisson line with 50Hz frequency. What can be said about the ...
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30 views

UHF RFID Microstrip antenna

I want to design microstrip antenna for UHF RFID. The chip I'm using is SL3S1013FTB0. I found some demo kits and found some antenna examples. One of them has small antenna that I'm especially ...
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29 views

Creating a 90 deg. circular polarized phased array using two Yagi

Imagine two 2.4Ghz Yagi (WiFi), one mounted with blades horizontal, the other's blades vertical, both aimed at the same target. Each has the same leg of its coax cable (Xmeasurement) longer (either ...
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37 views

Receiving DCF77 clock radio signal

I scavenged a loop antenna from a meteo-station that gets synched from DCF77 (77.5 kHz) clock signal. My idea was to implement a direct down-conversion with a microcontroller and decode the message ...
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2answers
476 views

Fixed a garage remote by breaking it

I have a garage remote that stopped working. I changed battery and it worked again, but only for a few days. I measured the resistance between the poles of the battery terminals and it was about ...
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Plot antenna radiation pattern in Matlab

I have the antenna radiation pattern exported from CST. The file is txt file format and contains the angles theta and phi and the directivity. First theta varies between 0 and 180° and phi is 0° and ...
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XBEE S3 PRO loses comms beyond 800 meters with a 7dbi Antenna

My XBEE S3 PRO loses some packets when transmitting 800 meters away from the XBEE Pair. Even though we used a 7 dbi car antenna with sma jack. we used a jack converter from sma to rp sma (if that ...
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2answers
545 views

Difference between Antenna and Filter

In RF front-ends the diagram shows an antenna followed by a band-pass filter. I am also working on a project involving a micro-strip patch antenna followed by a dual-band band-pass microwave filter. ...
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51 views

Fractal Antenna Design

I am trying to design a monopole fractal antenna using HFSS. My problem is with the excitation, I am trying to excite it with a connector with three terminals, where the middle terminal will be ...
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XBEE S3 PRO loses comms with another XBEE S3 PRO at anything beyond 800 meters even with a 7 dbi car antenna

I wanted to track a vehicle within a 15km radius. I am using XBEE S3 PRO connected with a car antenna with 7 dbi but it loses comms to another XBEE from point of origin in a distance of 800 meters ...
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2answers
57 views

op-amp amplifier for small loop antenna

I’m trying to make myself a ferrite core loopstick antenna for a crystal radio project so I’ve pulled the ferrite rod out of an old radio. The rod is about 1.5 inches and I’ve wound my own coil around ...
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2answers
29 views

Cellular chip antenna feedline width?

I have a chip cellular antenna from Pulse W3544B. In the datasheet it is said to make the transmission line 1.34 mm thick which I feel is too huge and also I wanted to make a strip line for impedance ...
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an fm antenna plug I've never seen before

I just acquired a Sony STR DN1080 AVR, and the FM plug on it is not coaxial or anything else I've seen before. Does anyone know what it's called and if an adaptor to a standard coaxial F connector is ...
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1answer
45 views

Struggling with patch gps smd antennas connections

I'm struggling with antenna connections to GPS module in my PCB design. My antenna is a smd passive patch antenna, "SGGP.25.4.A.02 from Taoglas". The antenna shape and recommended footprint is in the ...
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1answer
159 views

How can I attach a custom built antenna to the NodeMCU (ESP-12E)

Is there any possibility I can disable/remove the PCB antenna and replace it with a custom one, like a directional helical antenna? Can I just solder it on? I am an absolute beginner and have no real ...
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2answers
40 views

does adding Vias through the antenna feed line change impedance?

I have a GPS through-hole patch antenna, the through hole need to be connected to the bottom layer and then from there the feed-line flows to the GPS receiver. But I want the GPS receiver to be on top ...
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0answers
50 views

2.4GHz RF design losing signal

First time poster here, please excuse holes in the plot. I have a simple wireless design made of an MCU (atmega328p) and an NRF24L01 module, powered through a 3.3V regulator, talking to a similar ...
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2answers
38 views

Finding required BW with Bessel table

The FM signal (see image 1) is applied to a 50 Ohms antenna, and I am seeking the required bandwith with the Bessel table (image 2). From the FM signal, I deduced that the information frequency is ...
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2answers
52 views

How exactly a ground plane helps inproving antenna gain? What is the logic behind it?

How exactly a ground plane helps inproving antenna gain? What is the logic behind it? As per my general understanding, ground plane in reference to any perticular signal trace on PCB helps to absorb ...
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What is a difference between peak gain & avarage gain of an Antenna? How avarage gain is measured?

What is a difference between peak gain & avarage gain of an Antenna? How avarage gain is measured? For an antenna (e.g. GPS chip antenna) if avarage gain & peak gain given, which value should ...
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2answers
45 views

Partially Collapse Telescoping Antenna to Change Effective Length

I recently purchased a cheap RTL-SDR kit to experiment with SDRs and different frequency bands. This kit came with 23cm and 100cm telescoping antennas. I now wish to use the 100cm antenna to pick up ...
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2answers
69 views

What exactly does C/No (dBHz) mean in u-Blox GPS data?

In this related question I show data collected from a 6.5 hour run from NMEA sentences from a u-BLOX NEO-6 GPS module (datasheet, protocol spec) with an active external antenna via Raspberry Pi. I'm ...
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1answer
67 views

How to detect potentially poor antenna placement from GPS data?

Below is data from a 6.5 hour run collecting NMEA sentences from a u-BLOX NEO-6 GPS module (datasheet, protocol spec) with an active external antenna via Raspberry Pi. This is my first analysis to ...
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1answer
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A wave generator of 64db max and an omnidirectional antenna of 3.2db what db can have max?

I have this wave amplifier of 64db max and an omnidirectional antenna of 3.2db and I have to transmit a sine wave of 82Mhz, are they suitable for me? What is the maximum gain I can get? I need at ...
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1answer
56 views

Difference between two antenna types

I was trying to build a passive cell phone detector this evening, and finally got one to work. Along the way, I tried two different antennas: a 1 wavelength loop, and a dipole. I had the hardest ...
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2answers
48 views

Wanting attic antenna for LF and HF receiving

I know next to nothing about antennas and am hoping someone can tell me what antenna I need to pick up ham radio and FM signals on an attic mount antenna. I will have no need to transmit. My attic ...
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2answers
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What does the current distribution look like on an antenna?

This is more of a conceptual question, but I am struggling with understanding the current distribution on a radiating antenna. I understand how it travels, but how do we know? Is there some paper or ...
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0answers
42 views

GSM antenna connection from the phone does not make sense

I recently came across a phone (Samsung Galaxy Grand Prime SM-G530f) with trouble getting any network signal, I did some troubleshooting and ended up finding out that one of the pin(the GSM pin) to ...
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1answer
37 views

XBee Pro Antenna Options - do the U.FL antennas have better range than the chip or micro pad antennas?

Logically the U.FL dipole antenna will have better range than the other two options, as it's a larger antenna, but is this actually true? How do the three antennas perform in relation to each other ...
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1answer
39 views

ADC wire is picking up noise from cellular antenna [EMC]

I have a 5 wire micro jst cable with a line for ADC readings from an IR sensor that is picking up interference from the cellular antenna of the microcontroller. Will I be able to reduce this noise if ...
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1answer
56 views

Why do two antennas have to have the same polarization?

I have a linear horizontally polarized transmitting antenna and a dipole antenna, polarization mismatch losses can be approximated by 20log(cos(x)) where x is the misalignment angle. What is ...
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1answer
154 views

What antenna is this?

I just disassembled an external FM antenna designed for an old Asus laptop. I expected to find some circuitry and a monopole or some other simple antenna. However, what I found was the antenna shown ...
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1answer
33 views

Reconfigurable antennas at base-station

Can reconfigurable antennas be used at base-stations and cellphone towers? I read that MIMO antennas are used at base-stations for 4G systems (and will be used for 5G). Are these antennas ...
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Creating a balanced dipole from two monopole chip antennas for use on small PCBs

I'm trying to use a monopole chip antenna on a PCB much smaller than the one recommended in the datasheet. I am wondering if I can get away with a much smaller board by using two monopole antennas ...
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2answers
72 views

I don't know how to choose an adequate antenna

I need to choose an antenna for a long range free space communication (~10km), and I currently have a receiving antenna, but I don't understand enough to be able to pick an adequate emitter. The ...
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1answer
41 views

Equivalent Series Resistance of 13.56 MHz RFID Antenna

I am designing a system that uses the MFRC522 by NXP Semiconductors and I am having a bit of difficulty designing the antenna. NXP provide an antenna design guide under the application note AN1445 ...
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3answers
1k views

What is the “maximum power” of an antenna?

I was reading the datasheet of an antenna and I came across the parameter "Max. Power (total)", measured in Watts. What does this stand for? Can it be measured to check that the datasheet is right?