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I am new to this forum. I am trying to measure the electric field strength in a given mode between two points in a ridged waveguide. How do I do this? Specifically, I want to find the electric field strength across the mid points of the ridge of a ridged waveguide at either port. I appreciate anybody (...)
hi, am doing my final project at the university of zambia africa. somebody help me with how to simulate or write a matlab code for a 3D plot of a gsm base station antenna electric field strength that is its variation as u move away from the station, that is keeping in mind the type of antennas used. also the code for (...)
in a general case you should know if yhe target is placed in far field, near field or in the "very" near field (induction rather radiated). For the target in near or far field illuminated by the main lobe (boresight direction) the gain of the transmit antenna is NOT important. The 1st approssimation is to (...)
Hi. I am currently designing an antenna that needs to have a high magnetic field strength. Is there any specific features or golden rule that i need to follow on to get something out? Thanks in advance.
Two equal power signals summing together linearly will indicate as 3 dB higher. If you have two sources, and are radiating them and tying to measure 1 meter away, yes there can be higher and lower indications as you move the receiving power meter around. It is most likely because of the geometry of the two antennas, or reflections from nearby o
I am trying to determine the power level I should be using in a amplifier for generating an electric field at a distance . For example to generate 30V/m@ 1m until 1GHz. I have considered cable loss , antenna gain, VSWR mismatch at antenna and air loss to obtain the required power needed in the amplifier. However the value obtained is (...)
Does anybody know how to do a GTEM field strength measurement (V/m) when the ETSI standard suggests a methode using a substitution antenna and SG to read an amplitude in dBm?
I'm a freshie in the RF field. My antenna's field strenght is insufficient for some of the card so I plan to add in an amplifier to the design. Theproblem I'm facing now is I do not know how to increase the field strenght without introduce the noise, phase shifted and losses into the signal? Is there any reference design i (...)
Hi, Would anybody here happen to know an equation that will take in the magnetic field strength of two magnets separated by a given distance, then give me the magnetic field strength at the point halfway between them? ~ed.
hi guys any help me with this? A metal Spher, suitably insulated from earth, carries a charge of 0.25?C. the radius or the sphere is 150mm what is the field strength at the surface of the sphere? (surface area of the sphere is 4(pie)R2) cheers There are two basic ways of calculating this: a) the short way: reasoning
Excellent article/test report on Electrosmog meters, RF field strength power meter on the market. any one interested in the measurement of Electromagnetic field strength from Mobile phone, Wifi, microwave oven, AC power line, EMF, and transformers which might affect the human health should read it. from (...)
Hi, everyone I am an undergraduate student in antenna engineering. and i want to pursue a master's degree, would u please to give me some suggestions about the selection of the university? which university is famous for Microwave and Electromagnetic field, especially in the field of antenna? Thanks a lot! regards
I want to draw the gain pattern of uniform linear array and uniform circular array. But I don't know how to normalize electrical field into antenna gain. Here is my MATLAB code in UCA. E0 = 1; theta_0 = 90/180*pi; phi_0 = 0/180*pi; N = 8; lambda = 1; d = lambda/2; a = d*(N/2/pi); k = 2*pi/lambda; phi = 0.01:0.01:2*pi; theta = 0.01:0.01
hi I'm using the CST MWS to simulate the UHF RFID near-field loop antenna, and i modelized the antenna as following. But i don't know what size of the loop is suitable? How can i get the right geometry of this loop? this kind of antenna, i used "dis
Hi, i'm working currently on project where i have to know the magnetic-field around different conductor shapes. I think it would be good to simulate this with an EM-Simulator. I have access to CST MWS and EMS and have some experience with simulating RF-behaviours in the time domain. But i don't know how to start with my problem. It' quite
hello friends I am trying to simulate plane Electromagnetic wave received at receiver. The objective of this simulation is to understand about Statistical properties of resultant electric field strength in multi-path environment. I am wondering how to implement given electric field expression in matlab. I am on learning curve in (...)
Hi, In the following image. 94995 Since the two magnets 1 and 2 are of same magnetic field strength, the magnetic field lines from north pole of 1 to south pole of 2 get completely bonded(a). Similarly the north pole of magnet 2 to south pole of magnet 1(b). If say magnetic field strength of magnet 1 (...)
You can not measure receiver sensitivity without modulated signal generator at input signal frequency and level meter to measure signal/noise ratio or BER of output, demodulated signal. Kind of instruments depends on type of modulation you are using.
I understand you would like to measure E-field strength (expressed as power density, uW/m2). Here are a few links to RF field strength meters:
You can manage the problem by using tuner-IF section of a TV receiver. It has I2C for channel selection and IF section with video and sound demodulators. IF amplifier-demodulator chip has AGC pin which gives a voltage proportional to antenna signal and it can be used for signal level measurements.
I need to design an antenna and a rectifier circuit at 27 Mhz in order to measure the strongness or weakness of the 27 Mhz signal by multimeter. please give me instruction for calculation of value of the single diode, rectifier capacitor, resistor Thank in advance
Dear all,,, I was woundering how to measure the total electric field strength from different simultaneous sources at a certain point. what I know is that the antenna factor is useful only if there is an incident plane wave from one direction. what if there were more than one plane wave? how can the (...)
Hello All, I have a question about incident electric field on an antenna. Suppose an electric field E_inc (for simplicity I am assuming this field to have only one polarization component - say V) is incident on a vertically polarized antenna. The current induced in the antenna will be (...)
Dear All, I want to measure the distance between two objects. One is Wireless Transmitter (1st Object) and the other is Wireless Receiver (2nd Object). In between two objects, there can be many (hard) objects. But, I have to measure only the distance between Wireless Transmitter (1st Object) and Wireless Receiver. Is that possible? help will
Hello antenna experts, I am trying to measure the peak of ac voltages across loop antennas. The more accurate, the better. I wonder what equipment I should use? Will a digital oscilloscope suffice? The voltage could be lower than ~100mV. And also, I'd also like to observe the phase difference between two voltages. Please advice some (...)
For weak signals(less than -60dBm), How to measure?
SAR is a measurement of near field strength. Somebody say SAR is proportional to antenna gain and pattern. But antenna gain is from far field measurement. Therefore, I think SAR can be reduced even using a larger gain antenna. But I don't know how. I (...)
has several free and shareware programs. One combines antenna modeling with propagation and shows a map with field strength contours. is a government site with propagation software for free.
Anyone has the MATLAB code for the far field of a dipole antenna????? Regards
If you want to measure the input impedance (S11) of the dipole, you'll have to use (or design) a balun. The dipole is a balanced antenna and cannot be measured as a single-ended device, e.g. a resistor, etc. Once the balun is ready, the "easiest" way is to design a TRL calibration kit and enter its data into the network analyzer. Hope (...)
surface electric field on antenna is known, how to get the antenna electric field of far field, it is said that, we should use dyadic Green functions, I don't know the detailed process, plese give me some advice. Thanks in advance.
Hello! Could please someone help me with the formula for calculating the antenna factor of an ideal dipole? antenna factor is for calculating the field strength in dB?V/m when you have the output voltage of the dipole. I remember that it is 0 for either 30 or 40 MHz, and changes 6 dB when you double the frequency, but (...)
The return loss measures the reflected wave to the incident wave, that is RL = -20 log(Γ). So, a return loss of -10 dB means that the reflected wave is 10 dB lower than the incident wave. This is approximately equal to a reflection coefficient of 0.3, so 30% of the incident wave is wasted. Observe that this is for a voltage or a current wave,
Hi How can we measure if an antenna is Circularly polarized as its merely not possible to measure E-field. :D
I want to interface radio to PC plz note in mind i want to measure the electromagnetic field strengths of different FM, AM, TV stations can any body help me , or else is there any device that can be used to do it ,or any software
hi all,i have little question of cst how can i polt the field of any antenna at any position(not near field nor far field) i make horn and put probe in my desired postion ,so how can i measure field I(i.e. how could i rotate the probe to measure the field (...)
Hi, I got a project that needs a 1Ghz AC magnetic field at 10cm from the antenna. I am planning to use a coil as antenna, and the field strength ideally as high as possible so the AC current in the coil should be as least in the order of few hundred mA. Ok, I have never in my life touched high freq (...)
Hello i want to ask that; "what is the difference b/w antenna near field and antenna far field?" Please explain in detail also upload any document (.pdf or other) related to it. Thanks in Advance
I know how does a transmitting antenna work, you have a piece of conductor and apply a sine wave and it generates EM waves, you have patterns and stuff. How about the reception?
Anyone has info on the broadband dipole antenna, the one like a ball with two half cup together like a ball on the top and with a stick connected to the power meter used mostly in the EMI testing. any detailed info on how the dipole is formed? and connected ? there are 1 axis and 3 axis types, is the ball shell part of the dipole or th
Hi evryone my problem is that i want to measure the signal strength of the signal received by my WLAN card,i have used NetStumbler but it only makes a graph of SNR out of it. what i want is to measure the exact value of SNR of signal strength. ive also read somewhere else that it can be done in C++ . if anybody knows how (...)
Dear All: I want to show the dBm unit in the specturm when it connect with directional antenna. But the AF unit is dBuV/m . The spectrum can only show dBuV unit. I try to transfer the AF unit to dBi. Ex: antenna at 500MHz, the AF=18.707 dBuV/m. I will use the below formula to transfer the unit. AF (dB) = 20 * log ( 9.73 / [lambda * sqr
Colleagues, How difficult is it to measure signal strength of an RFID tag with a given code in presence of other tags? If there an existing signal structure where it would be easy to do? I would appreciate any references on this subject. Thank you, - Nick
You don't provide much information at all. - involved RFID standard? - utilized reader chip? - did you measure the field strength at the card's location with a test coil? (A test coil is basically an oscilloscope probe with a wire loop of known area) - did you see any load modulation (card response) with the test coil?
You may need to know a measurement problem to decide how to measure.
An electromagnetic wave propagating through space is always a plane wave. It means that its E and H component alternate in a sinusoidal manner, perpendicular to the axis of propagation. It is a "transversal" wave. Only close to radiators that generate the wave, the shape of the wavefront runs off a "point", so it is spherical. As it travels fart
For lowest noise, impedance matching of receiver antenna is mandatory. There are however many cases, where other objectives are more important, e.g. small size, high bandwidth, or precise field strength reproduction (for measurement antennas). You should also consider, that a receiver is not necessarily (...)
Hi, I am looking into 13.56MHz antennas to use for ISO 14443 and/or ISO 15693 applications. I've developed prototypes in the lab that are working, but I have a confusion on the 'Q'. The antenna I'm using is a loop antenna, and I match it by using a couple of capacitors. All of the sources I've read have said to set the Q of the (...)
Hi all.. I'm newbie in design antenna, so..help me please.. :D i want to make a spiral planar antenna with frequency 13,56 for RFID reader, is it possible? how about the size, number of turn and the other caracteristic? can you give me some journal about it? because i need more refferences.. thx...
hi all.. i design planar antenna in frequency 13,56 MHz in HFSS. it's planar spiral antenna.. its reflection coeficient still above -10dB. it's about -3 dB. i have change the position of the antenna, but it's stil not in matching condition.:cry: How to match this antenna? thx.. :D