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267 Threads found on Input Impedance Antenna
I would guess the transmission line Z is around 70ohm like other 1/4 wavelength dipole antennas. According to literature, it's more complicated. As a simplified idea, imagine that the characteristic feed line impedance loaded by the dipole elements equals the antenna input impedance. So it's always higher (...)
how to calculate the minimum separation between body and wearable antennas. if it's very small the absorption because of body will be high and and also it effects the input impedance and the radiation pattern of the antenna. one good approximation is to be keep the distance of (2d2/lambda) from the body for which results (...)
I need simulate an antenna in HFSS for RFID. The internal impedance of IC at 915MHz is 12.8-j248 (NXP UCODE7). This is a serie impedance. To simulate this impedance I use a Lumped port with equivalent parallel resistance Rp ~ 4.837K and a capacitance of 0.7pF in parallel using a lumped RLC. Both in parallel connected to a (...)
The antenna efficiency (or radiation efficiency) can be written as the ratio of the radiated power to the input power of the antenna nu_Rad=P_Rad/P_in The total efficiency of an antenna is the radiation efficiency multiplied by the impedance mismatch loss of the antenna: (...)
Dear all, I would like you to clarify a point that I don't understand very well. when an antenna resonate it means that the Imag part of the impedance is equal to zero, but while reading I found a paper with totally different results which I am attaching the confusing figures of the complex input impedance of the (...)
there are differential op amps that actually work pretty high in frequency, like 2.3 GHz for the ADA4927-1 from analog devices. Maybe use those. You could convert to single ended signal after the input op amp.
Problem is also that the bridge requires sine rather than square wave input. A filter (e.g. low-pass) is required. Could insert an amplifier too.
Hi every one! The input impedance of a single ended antenna is usually assumed to be 50 ohm, I wanna know what is the typical input impedance of a differential antenna? I mean if I want to match the impedance to what my PA needs, what impedance must be (...)
Can you explain about the input impedance of the antenna(if possible provide some video links)?
Inverted-F antenna it will work better than most of chip antennas. Your inverted-F design should work fine, mainly because you have available a solid ground under the antenna (which is a main requirement for this type of antenna). The antenna might need some input impedance (...)
Why does the manufacturer specify both the input and output impedance of the balun? A balun can have various impedance ratios between balanced and unbalanced ports. Usually the input impedance of a full-wave loop antenna is about 120 ohms, so for a given 50 ohms unbalanced port you need a (...)
I tried to create a loop antenna, consisting of a single closed loop for 144.3 MHz. I wanted to set the diameter so the real part of the input impedance was 50 Ohms, and then tune out the inductive part with a capacitor. So I set up this HFSS model, and found a radius for the loop where the input Z is 50 + j X Ω. So I (...)
S11 of the antenna and the transmission line impedance, they are different things. Measure the impedance of the transmission line alone, and later measure the input impedance of the antenna without the feeding transmission line (if is possible). Measure the real Er of your FR4 PCB, because (...)
Hello, I have an UWB antenna that is composed of double sided substrate. I noticed that when i round the lower vertices of the upper side (patch) or the upper vertices of the lower side (ground) the matching improves, i reviewed the imaginary and real part of the input impedance and i found that they do get improve as the rounding (...)
Hello I designed a simple corner reflector with HFSS and I set terminal impedance to 75 ohm.Here is my Hfss output S11 and input impedance of my antenna. 126392 (So at F=8 Gighz we have S11=Gama=10^(-10.7358/20)=.2905 126393 (as you see at the F=8Ghz image part is approximately around 0 and so w
I do not have access to the fulltext of the following two papers. Anyone can help? Thx in advance! 1) R. F. Schwartz, input impedance of a dipole or monopole, Microwave J., Vol. 15, p. 22, Dec. 1972 2) J. B. Andersen, Admittance of infinite and finite cylindrical metallic antenna, Radio Science, 3, 1968, pp. 607-621
Hello what is antenna input impedance variable in HFSS? Terminal Port Z0 or Terminal Z parameters? Thanks
zin=0.05+j33.36 If the real input impedance of your antenna is actually 0.05 ohm, start with redesigning the antenna. Matching this tiny radiation impedance is a helpless undertaking.
you need to plot the input impedance of the antenna which is, in the case of single port network, Z11. The real part should be around 50 and the imaginary part should be crossing zero at that point. An alternative way is to plot S11 and the antenna is considered to be matched when S11<=-10dB.
coaxial fed in place of microstrip fed, i never tried it before. usually fed determines the input impedance of the antenna. like if you find my comments are helpful.
Hi All, I try to design SRR antenna with additional capacitance in between gap so that it will match my 50 ohm input impedance.But it doesn't show any effect of S11 when i change the value of capacitance. Can anyone help me on this matter.Here I'm attaching the CST 2014 file. Thank you in advance.
Hello Ali & Hocine Most probably the matching between chip and tag input impedance... Anyway, if you would like to check your .cst file, please share it with me in order to validate it. Thank you
One should not change Z11, your problem in matching chip impedance to the input impedance of the Tag antenna.
hi everybody. i am designing a cavity backed spiral antenna in 2-18GHz. i used microstrip balun for transforming from 50ohm input impedance to 188ohm spiral impedance. both balun and spiral have good behavior . and spiral have good patterns in all frequencies. but when i attach this two part the resulting radiation
hii every one, Pls tell me how to calculate the height and radius of probe,coax,coax pin and also give some information to perform impedance matching since solution data shows that input impedance is 50 and port impedance as 25. pls help me to solve this problem
hi guys ,i need all your help i simulated the 14.4MHz Bilayer rfid antenna in CST,and now I try to put a IC(Load modulation resistance=1.1 kohm,input capacitance=24pF). QUESTION 1.if i want to simulated the IC in this antenna,how to design my port?(I always use discrete edge port,impedance is (...)
Hello to everyone! Because I have seen many opinions about input impedance and mutual impedance on CST, I want to clear this out and however this will be a precious thread for other members too. Imagine that you have simulated an antenna on CST and lets also imagine that in the navigation tree we have the S-parameters (...)
I have trouble to the HFSS, i have these questions. I would be grateful to anyone who would help me. I made the hf RFID at 13.56 MHz,now I need to patch antenna with IC ,the IC input capacitance is 97 pF,but the hfss need me to input resistance and reactance so I use ADS to get Zin=50-j121.58Ω ,Is this a right way? [url=obrazki.elek
Do a EM simulation and see input impedance from S11 on the Smith Chart. Then design a matching circuit ( L-C or Microstrip ) to adapt this impedance to 50 Ohm..
There are discussions in C.A. Balanis' classic antenna book, as I can remember. As a rule of thumb, try different feed locations along the middle line of the patch. A feed location at the patch edge leads to the maximum input impedance, while a feed location at the patch center brings about an equivalent short. Therefore the feed location (...)
Hi, I have some s-parameter blocks in ADS and an antenna array in HFSS. Is it possible to cosimulate so that I can excite an input of the s-parameter block and view the resulting radiation pattern in HFSS? I can do this manually by altering the port impedance, phase, and magnitude in HFSS but it is a hassle. Does this question make (...)
Dear All: I would like to know the principle of why complementary antenna has a constant input impedance.Could someone tell me or show me the documents?I would appreciate very much
Each capacitor appears Zc=1/(2pif*C) + ESR. the diodes are dynamic resistance and depend on size. You wont be able to match the impedance because the coupling current and spacing loss makes the input impedance high and the closer you get, it can drop below 50 Ohms. You are much better off using a step-down inductive coil (...)
What impedance did you use for your lumped port? A complementary Archimedean Spiral should exhibit an input impedance of 188 ohms.
Your question is missing many necessary informations: - what's the output impedance of the "impedance matching IC"? (Is it a ceramic chip balun?) - what's the actual antenna input terminal and designed impedance? - are there more PCB layers not shown in the screendump or just top and bottom? (...)
Another possible solution.. If you know the components' values and part numbers, you can build the same circuit on a seperate PCB and measure it standalone. Then measure the input impedance of the circuit at the antenna input after that extract the s-parameters of the first copied circuit from these second measured (...)
I realize it's hard to answer my prior question without more intimate knowledge about my experiment, so I'll ask another questions....can someone please comment on the accuracy of HFSS's input impedance results? I ask because I was trying to design a dual band high impedance antenna, and HFSS showed great results howe
Autognd ports are used as internal ports, they need calibration plane. You should use standard ports. No, both port types are fine. The autognd will create the ground access in vertical direction (via) and the standard box wall port will create it in horizotal direction. Of course, for the autogrounded port, w
From this picture, you can't calculate the working frequency of LNA. This picture only provides you a matching solution in PCB board. C11, L1 is the input L-type matching. C16,L3 is the output L-type matching. C8 blocks the DC current.
Hi in literature sometimes we give the input impedance as a function of L / lambda0 (normalized length) Please, can someone show me how to do to plot it as a function of L / lambda in HFSS for whatever structure (e.g. for a dipole, or a patch antenna). of course I know how to do it as a function of frequency. Thanks
Note that for very small dipole antennas, the input impedance is capacitive, which means the impedance is dominated by a negative reactance value (and a relatively small real impedance or resistance). As the dipole gets larger, the input resistance increases, along with the reactance. (...)
Resonance (when looking from a 50 Ohms port) is not required for the chip as the chip doesn't show a real load to the antenna. You need to have an almost conjugated match. If the chip has an input impedance at operation of 40-j60 Ohms (just an example), your antenna should present 40+j60 Ohms to the chip to have a good (...)
for radiation pattern, go to Hfss/Results / Create report / Farfield / Radiation pattern for S11, input impedance will affect the s11 parameter. most of the times, your input impedance should be 50 ohms, and your matching by choosing proper width and height of microstrip feed line could be well...
Hello friends, I am new in antenna design and I am trying to design a layered MLA for a mobile handset. I prepare my design according to a paper and do some modifications in sizes. I use HFSS 13 for simulation and I started to use HFSS with this project. I used wave port as excitaions and radiation in a sphere. Here is my design and you can se
A textile antenna should not be different from a "normal" antenna. You can characterize your material (electric conductivity or er of the substrate) and then use this in the simulation. I think it is not possible to get the input impedance at arbitrary points, since this means that you would feed the (...)
i want to draw Real &Imaginary part of impedance v/s frequency curve for Dielectric resonator antenna in Matlab using FDTD..kindly help me for codes. its very urgent for me. thx in email id:
9579295801 Hi Guys, I am trying to replicate the antenna in the attached file to resonate at 2.45GHz but its is resonating at more than twice that frequency. The reflection coefficient and antenna input impedance are very bad. Can some one please guide me how to optimise the reflection coefficient to <= -12dB
Can someone help me to design this antenna ? spiral antenna -working band: 400-4845 MHz; -standing wave ratio ≤ 2; -50-ohm input impedance; -the ellipticity ratio ≤ 0.7; - - - Updated - - - P.S.: i am new to hfss software
A helix with a ground plane behind it has impedance 140 Ohms. This method is to include a 83.6 Ohms quarter wave electrical length line between the 50 ohms input and the helix. One physical form of this is to make the first quarter-turn be a "Lecher Line", which is a single line set over a ground plane. It becomes a wider tab over for th
sir how we design inset feed for tooth like slot on patch antenna.if inset feed cross center of patch how we calculate input impedance..