Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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

0
votes
2answers
35 views

Z=50 and Xs=0 but SWR is not 1.0:1

I measured an antenna with a VNA and differently to all other cases the SWR isn't low as expected. Here are some screenshot showing this: Similar situation, on the same antenna in the same ...
0
votes
1answer
29 views

Comb generator vs. known EMC emitter - different measurements in shielded tent vs. 3 meter chamber

I've got an EMC testing setup of a 1 meter shielded tent, and a very high gain EMC antenna. I'm seeing a phenomena that I can't quite explain. I have a known product that was tested in an accredited ...
10
votes
3answers
4k views

Do square wave exist?

If we send a square waveform through an antenna, will we get square electromagnetic waves with electric and magnetic fields looking like squares? Also, since there is an abrupt/almost jump in ...
0
votes
1answer
54 views

2.4 GHz Chip antenna layout

I am am new to RF design and I need to place a chip antenna due to space limitations. The only antenna that is easily available to me has a very weird layout. There is no physical connection from the ...
0
votes
0answers
36 views

Single-frequency AM Receiver?

Previously today, I tried to make an extremely simple AM receiver without a tuner. It didn't really work (I'm still trying to work on it), but I also tried to make an AM receiver that is tuned to one ...
0
votes
0answers
35 views

Minimum antenna separation

I am trying to design an RFID system. The transmit antennas will be placed along the length of a 12 by 3m rectangular truck container and be placed at the midpoint of the height of the container. The ...
0
votes
0answers
32 views

Planar Inverted F Antenna Printing

I am trying to get a planar inverted F antenna milled via Pcbway. I created the gerber files using CST microwave studio. I keep getting bounced back with the error: "No keepout layer(board outline),...
8
votes
2answers
1k views

Circuitry of TV splitters

I'm trying to understand the circuitry of TV signal splitters and associated boosters/amplifiers, and I have two questions. My situation is as follows. I have a TV aerial (antenna) in my loft. It ...
0
votes
2answers
34 views

coplanar waveguide vs microstrip for gnss and cellular?

coplanar waveguide vs microstrip for gnss and cellular? I read on internet microstrip is better for signals <30Ghz but some gps manufacturer (Delorme) said that coplanar is most efficient so it's ...
0
votes
1answer
27 views

Influence of incident signal on antenna S-parameters

I'm interested in determining the phase of an incoming signal using a 1-port Vector Network Analyzer (VNA). The antenna would be receiving a signal while connected to the VNA. I know that the S11 ...
0
votes
0answers
14 views

finding polarization of radiated far-zone electric field

I am given a question in which I have to find the polarization of the radiated far-zone electric fields when phi is 0 and 90. Why are the following formulas used respectively? For phi = 0 $$ E_\...
0
votes
1answer
30 views

Making an omni anntena for PA+LNA+Antenna

I have several NRF24L01 RF modules that I would like to use to transmit data from a car to a ground station. When testing the modules, I have found that the data transmission is only successful when ...
1
vote
2answers
25 views

Standing waves feedline length and dipole antenna feedline

so I have a question regarding reflections/characteristic impedance and there relation with a quarter wave transformer and its feed line. Now I have found this video very useful for visualising what ...
0
votes
0answers
69 views

How does this double-tuned antenna work?

I am trying to understand how the attached circuit works, for tuning a transmission/receiver antenna (L1) for double frequency (HF, 500 MHz on the left output and 202 MHz LF right), to be used in ...
0
votes
1answer
45 views

Full wave rectification with only an antenna input?

I am designing a receiving circuit and would like to do a full wave rectification of a sine wave signal received from an antenna. My problem is figuring out how to isolate the two ground signals of ...
1
vote
0answers
22 views

NFC Antenna Feed Lines

I've designed a number of boards in the past that use NFC but I don't think the RF performance has ever been exceptional. These boards have an NFC chip (generally the STM M24SR64-YMN6T/2) connected to ...
0
votes
0answers
27 views

Antenna formed from the RF module shielding wall and cover

Can anyone provide details how an antenna can be designed from RF module shielding wall or cover? More specifically if any company is making this kind of antenna product for general communication or ...
2
votes
1answer
41 views

Where to connect the VNA during matching network tuning

I'm trying to design the matching network between an antenna and its transmitter, running at 868MHz, as shown below. There's probably about 20mm between the transmitter output and the Pi network. ...
0
votes
0answers
46 views

Question about 50ohm impedance matching circuit

I am implementing rf energy harvesting circuit. The rectenna is working at 915MHz and the impedance is 50Ω. I think L-matching may be the easiest. However, I don't have the vector network analyzer. Is ...
0
votes
0answers
29 views

Why is the length of a cable-type radio-antenna usually determined by c/f regardless of the preceeding pcb trace length?

especially when dealing with low power IoT-devices or these arduino-style radio-modules that don't come with fixed rod-like antennas but rather those cable-type antenna-tails, the length of the ...
0
votes
0answers
41 views

GPS and Galileo signal reception with a broadband antenna

I have a passive antenna that covers a wide bandwidth (1.25 - 2.45GHz, RHCP, omnidirectional) which I'd like to re-purpose for Galileo signal detection. I don't have an option to get an application ...
0
votes
0answers
38 views

Vertical distance from PCB antenna layer to ground plane?

I know the basic design requirements for pcb trace antenna, no ground place below or above the traces, impedance matching etc. But the design layout recommendations for pcb antenna doesn't seems to ...
0
votes
0answers
33 views

Diy Bluetooth speaker antenna

I am building a Bluetooth speaker with a 50watt Bluetooth amplifier board which has a pcb antenna,I would like to get around 150to 200 feet range line of sight, what type of antenna would be best for ...
0
votes
1answer
43 views

Intuition behind ambiguity of direction using linear array

I have recently started studying array signal processing. I am struggling to understand the intuition behind ambiguity of direction using a single linear array and how it is solved using two parallel ...
1
vote
1answer
49 views

Reflection of Electric field in open-circuited transmission line

Consider a parallel-wire or parallel-plate or coaxial transmission line, carrying TEM wave, which we model as E,H,V,I, each having a forward(+) and backward(-) wave. In terms of V,I, we define ...
0
votes
0answers
36 views

Reactance of a dipole antenna

I am interested in calculating the input impedance \$Z_{in}=R_{in}+jX_{in}\$ of a dipole antenna numerically. However, I am unsure how I would compute the imaginary part of the impedance (\$X_{in}\$). ...
0
votes
1answer
28 views

Is it possible to change gain on Adafruit PN532

Is it possible to change the gain on an Adafruit PN532 board? I need to LIMIT the range in order for it to NOT interfere with another PN532 installed close by. The board is to be used with an ...
0
votes
0answers
22 views

S11 parameter measurements of NFC PCB antenna by VNA

I'm trying to measure the S11 parameter of the NFC PCB antenna (actually PCB coil) by VNA. Desired Smith chart pattern is like the below picture (probably with different values, because of different ...
1
vote
0answers
46 views

Cycle time / transmission cycle in short range automotive radar

I am somewhat newbie in the radar field. I am reading SRR20X-datasheet from Continental. I have two question. What are definitions of Cycle time/transmission cycle (second page)? And in the document,...
1
vote
2answers
114 views

RF Antenna Matching circuit and PCB design for 868 MHz SigFox device

I'm designing a Sigfox sensor device based on WISOL/SFM10R1 a SigFox verfied module by WiSOL and Atmega328. I need to understand the parameters for 868 MHz RF Antenna Matching circuit and PCB trace ...
0
votes
1answer
63 views

(Antenna impedance matching) How to find the load impedance

I'm working on a project that requires impedance matching and I'm going to match a 50 Ω antenna to a RF amplifier SST12LP22. However, I'm not sure how can I get the impedance of the amplifier from the ...
0
votes
0answers
89 views

adding an antenna to a toy PCB, where can I ground it? is the negative battery cable ok?

I want to replace the antenna on my toy quadcopter with a better one, to improve reception. On toy quadcopters the antenna is just a simple wire soldered to the quadcopter circuit board (with no ...
2
votes
1answer
131 views

How to measure radio signal strength

I am building several types of radio antennas, and I would like to test which is the most effective. I am wondering: What is the best way to measure the strength of the received signal? It is at ~...
1
vote
1answer
27 views

voltage-controlled frequency tuning of an antenna

I am looking for an antenna whose frequency could be changed by an applied voltage signal, I am not sure what is the name of this kind of antenna or whether it exists or not. By searching on google ...
2
votes
1answer
167 views

Sub 1 GHz communication - long range at 500kbps. Is my range estimate roughly correct?

When researching long range medium bitrate RF comms I came across the TI range. The TI CC1201 transceiver claims -97dBm sensitivity at 500-1000kbps. If the system is on the 868MHz band which is ...
0
votes
1answer
41 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 ...
0
votes
0answers
63 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 ...
0
votes
0answers
41 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. ...
0
votes
0answers
43 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 ...
0
votes
2answers
70 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 ...
0
votes
0answers
10 views

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 ?
0
votes
0answers
47 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 ...
7
votes
1answer
245 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 - ...
13
votes
6answers
4k views

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 ...
0
votes
1answer
113 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 ...
0
votes
0answers
37 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 ...
0
votes
0answers
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 ...
0
votes
0answers
47 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 ...
2
votes
2answers
479 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 ...
0
votes
0answers
89 views

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 ...