Search Engine

474 Threads found on Antenna Circuit
Hi , Guys I have UHF FM Transmitter with power about 5W I want it to send video signal through AM the carrier frequency here the important section of schematic : 135260 I tried to inject signal in Q407 emitter ( i think this make low level AM ) after remove R408 the picture shows up in my TV with lot of noise and
Falstad's simulator is free, animated and interactive. By reducing the timestep you can use frequencies in the GHz. Its antenna model provides three simultaneous broadcasts on AM frequencies, which you can tune a detector to pick up individually. LTSpice is free and more sophisticated than Falstad's. It contains models o
Hello EveryOne !!! I'm a student and i'm writing a thesis about the fault diagnosis in Microstrip Patch Array antennas using a SingleValueOptimization Algorithm. First, i have to implement a patch array in ansoft designer V2 using the circuit Simulator (Microstrip Component) without planar EM. How i can do it ? Thank you a lot !!!!
I think the diagram you show is quite primitive. The antenna will influence the transmitted frequency. It would be better to use a buffer transistor at the output of the oscillator (repeater on emitter maybe). I don't think you need to change from bipolar to FET. The TV spectrum is very large, from 48 MHz to over 800 MHz. What channel do you want t
What does physically happen when a receiver antenna in Open circuit/ and short circuit mode is exposed to RF signal? Is the power reflected back?
Hi, I would like your reviews on this circuit The author states advantages over mosfets and he uses tubes.
When we see the antenna parameter, there is the impedance which it's always real (75 , 50, ... Ohms) But the impedance antenna is \left\vert{} Z \right\vert{} = \sqrt{{R}^{2} + {( \omega L - \frac{1}{\omega C})}^{2}} or it's just the real part of Z? I think it's the first one, Because the antenna always has and inductance and
i am designing a cavity backed bowtie antenna.what is the need for cavity in antenna designing.if i am using a cavity box ,should i have to use a groundplane .how to calculate the dimensions of the cavity box.what material should be assigned to the cavity box.
I need to check EM properties of my antenna feed network, so to save time, I want to replace patches with equivalent open-circuit "loads", each with input impedance of 50Ω. How would I go about it? I can use stub matching to design a termination given the load, but how do I do that if my load impedance is infinity? I know it can be done sin
I am working on a pattern reconfigurable antenna and for this i need to bias the PIN diode from a battery through bias line. For this I need a RF choke inductance to isolate the ac from the bias line. I have seen different value of inductor is being used by different author. Is there any specific formula to select the RF choke to select for frequne
Hi, I need to design a circuit that will provide power to a TV antenna amplifier. My constraints are : * Characteristic impedance : 75 Ohm, * Power supply for antenna amplifier : 24V @ 100mA and * Available power supply : 9V @ 1.6A I think I will base the solution on a step-up converter. But I have a concern about the harmonics of (...)
Hello everyone how are you. I am working on a circuit that has a SIM800 module with an external L Shape antena. The module is powered by a LM2596 DC DC converter. The problem that I have is during the module registering phase to the network. It suddenly resets and start o ver again. But if I hold the antenna with my hand or if I place a finger ove
Hi, I have a tiny electronic circuit (RF active antenna with fitted SMA connectors) and I want to enclose it in molten plastic or other resign, so that I can create a short of "rubber duck" antenna. The major concern is the SMA connector, which is fitted in molten plastic in commercial rubber duck antennas. This allows the (...)
Hello, We are designing a 20W SMPS which simply supplies 15V at 1A to an RF Phased array antenna circuit. (its for comms). Vin = 48V. We were wondering if it is overly extravagant to do this as an Half-Bridge LLC converter? Its just that the SMPS will be very close to the Comms signal processors and other sensitive circuitry, so we (...)
The answer to your question: Why do we use a short circuit line to the ground plane? is: For proper impedance matching. IFA is a variant of ILA (Inverted L antenna) which has an L shape and don't use this short transmission line for "proper" impedance matching as IFA. ILA gets the right port impedance changing the length and the shape above the g
I'm not acquainted with CST, but in HFSS you cannot do that (as far as I know). You need to fit the equivalent circuits from the Microstrip antennas chapter in Balanis book (probably two RLC tanks regarding the two radiating edges) and then tune it using for example ADS, until it fits the resonances obtained in CST or HFSS.
Hello, I found very cheap 433MHz transmitter/receiver kits on ebay (see image attached). They have poor range. I am wandering if one-transistor amplifier attached before transmitter antenna will extend the range. I have designed one transistor amplifier myself (see image attached) and doubt it will work properly. In theory (according LTSPICE
Does any one have any idea how to design a microstrip antenna as discribed in the following circuit and pictures The frequncy is 5.8Ghz thanks in advance for you help
As analog engineer, I have been asked to review a design before production. This design include an antenna on the PCB (see attached picture, about 5cm by 5cm), but the antenna design seems very strange to me. This emitter antenna must work in the band of few Hz to few 10 Hz (ELF band). A simple calculus tells me that the wavelength is (...)
Im designing a lightning protection circuit for GPS module that works off 3,3V and antenna line is used to feed antenna with 9V DC through bias tee. I have a gass tube discharge(GDT) element in antenna cable that should take the voltage down to about 90V, but I need help designing the low voltage protection stage that I (...)
for that shield to work, there has to be a "ground plane" somewhere inside of the PC board. you connect that metal shield to the ground plane in numerous places and try to make a faraday cage. unfortunately, since you need an antenna external to the are going to be deliberately screwing up the faraday cage, and may need to add a low
The circuit is not an amplifier, and is just a common base Colpitts oscillator with an antenna attached at the output. C5 is the feedback capacitor, and C3 is the base decoupling capacitor. C3 has low reactance at oscillation frequency (RF), and high reactance at modulation frequency (AF). This is a poor design, and if you touch the antenna, (...)
The difference is: 1- antenna is on the top the layer while EBG at the bottomof the layer 2- two layer, first layer for coplanar antenna and the second layer on the top EBG and the bottom full ground. then this two layer attached togather with spacing to avoid short circuit. The EBGs will have different behaviors.
Hello All, Please help me in plotting the gain in HFSS. I go through these steps: result/ far field report/rectangular plot /antenna params/ Peak gain or peak realized gain / and set solution in context to sweep and primary sweep to freq, and press new report, but the HFSS does not give me result. It keeps loading!! Please help. Kawther
Hello All, I drew an antenna as in one of the papers. I analysed it, and created the VSWR graph. It was as below 122628122629 A very high VSWR at the notch frequency. The VSWR in the paper was about 26. Why did i have a very high VSWR at the notch frequency? Regards, Kawther Hamad,
I think you can use PCB trace antennas. Inverted F-antenna, Meandered inverted f antenna etc.
I was thinking of the ideal and lossy transmission line models in circuit simulation programs, e.g. SPICE. It's important to understand if transmission line common mode waves are involved, if so a combination of multiple transmission line models may be used to model common mode and differential waves. What's the frequency range of your antenn
If your antenna had a built in resistor to ground, say 10k, it would be simple to have a 1~10M pullup and Cap for low current to activate a P-ch MOSFET high side switch to de-activate the circuit, then activate when antenna 10K to ground without degrading the RF. PC's use the same method to detect a speaker connected (<100 Ohm) and video (...)
Go only with the printed antenna. The worse printed inverted-F would work better than any chip antenna. The only thing that an inverted-F antenna needs to work well, is a good ground plane (which can be the metal shield of your circuit) and spend little time on tuning.
it is a mixer. It is probably a homodyne radar receiver of some sort. It sends out RF from a transmit antenna. Simultaneously, it sends a copy to one port of this "mixer" called the "local oscillator port". When the return bounces back from the ground, it is received by an antenna and input to the "RF Port" of the mixer. The resultant is a low
Hi Every one This is kico from shenzhen XCE company. We are a manufacturer of printed circuit board over than 10 years in shenzhen,china. Our products include microwave sensor&source circuit board/RF synthesizer circuit board/Satellite transceiver circuit board RF transceiver&Transmitter circuit (...)
I am doing circuit soldering but how I know which antenna speed is required and which software needed for Nokia 6600 mobile repair need diagram also and repair tips .Thanks
More information needed. I guess your "antenna" is a RFID reader coil. To extent the range, the coil current must be increased. Reducing the coil resistance should basically work in this direction, but the effect depends on the transmitter circuit.
2SC4367 has a typical transit frequency of 1 GHz (min. 600 MHz), so you're lucky if the circuit is oscillating at 900 MHz at all. You all want to use transistor with GHz bandwidth instead. Apart from this point, what's the value of C2? Is your circuit layout suited for 900 MHz at all? If you connected an antenna, it's frequency (...)
Most important aspect is the antenna coupling factor ( transformer coupling) THe gap between sender and receiver must be smaller than the loop antenna for reasonable coupling. THerefore tune each coil ( round or square) to resonate more maximum Q with a large diameter > gap. ( just like RFID's in store exits) This can be extended with high mu
So you just need to do Q spoiling? How fast does the coil energy need to ring down? I'm guessing that you're seeing inconsistent behavior because the switching isn't synchronous with the phase of the antenna current. Ideally you would switch on exactly when the coil current is at zero, but that means the capacitor voltage will be at its maximum, s
Hello Everyone... I have made antenna and tuning network which can detect MiFare and HiD iClass cards. i.e. 13.56Mhz... So for that i need to control unwanted harmonics of 13.56Mhz... I have designed antenna tuning circuit as per MiFare suggest. Card detection range in around 4 cm. So how can I reduce effect of harmonics??? And what (...)
Can you help me and take a look at this amplifiers? They are supposed to be antenna preamplifiers. On the left side is my calculated FET amplifier. On the right side the drain resistor is replaced with LC circuit that resonates on 14MHz. Yes I know, the input is 14.25MHz. I calculated it by mistake for 14MHz, but it's not important. The input signa
What is a better approach to harvest some radiated field from barbed wire parallel to an overhead high power transmission line ? : -A bridge rectifier at one end of a barbed wire against a grounded rod, or -A 60Hz LC tuned circuit from the barbed wire serving as antenna against a grounded rod. (plus rectification) -Or other ? And why? Not i
Hi All. My want to add GSM Internal and external antenna switching in my project. I'll use GSM Module with Antenova A10340 Internal Chip antenna and External SMA antenna connector. I want to implement a circuit so user can choose either internal or external antenna option. Can anyone advise how to (...)
Good Day Dear Members, I have designed the following rectenna in CST Design studio that works in parallel with the antenna designed at 900 MHz using CST MWS.(Fig1) I have placed all the relevant Voltage sources and probes in the circuit as shown, but Im unable to generate correct DC Voltages and Current at the output of the circuit. (...)
how to find input impedance of patch antenna in ADS and how can i match it to 50ohm using microstrip line
I understand that you have one model with two antennas, and each antenna is connected to a port. Now you want to simulates the interaction between the two antennas. First you get S21 from the 2-port simulation. Then, instead of creating two additional 1-port EM models (one with antenna 2 shorted, the other with (...)
Good Day Member, I am working on a rectenna that harvest GSM energy at 900 MHz and converts it into DC Voltage for charging a cell phone battery. From various literature review, I have made a simple patch antenna in CST MWS and designed its relevant rectifier circuit in ADS. The questions I want to ask are following: 1. In most of the rectenn
Is there any way to isolate the antenna ground from the rest of the circuit? I am using EMDS/ADS2009 for circuit simulation?
Hi everyone, I am working on RFID tag design and i want to choose the chip so i have chosen Alien higgs 4 , they mention in the datasheet the parallel capacitance input is equal to 0.89 PF and the resistance parallel input is 1800 K ohm but when i have read some papers they mention the Higgs 4 chips impedance is equal to (18-181j ) , so if anyon
Hi Again, I tried to find out how the last problem occurring and I see when I use small antenna this is happening much more and it depend to position of antenna too. So it seems it is RF effect on circuit. In the circuit there is polygon, is there any other ideas to decrease this effect ? BR,
hi, i must design multifunctional SRR-loaded printed monopole antenna. how can i add switches on SRR in HFSS? like this
Your transmitter is messy, I am surprised it works. Usually a 100MHz transmitter circuit is neat and tidy. The distance is increased when the antennas focus the radio beam. A Yagi antenna has good focussing.
That all looks good to me. You have the fixed regulators wired correctly. Watch out for the antenna connection on the module, at 5.7GHz the track width and spacing are critical if you want most output to reach the antenna. Brian.