Homebrew RF Circuit Design Ideas. Patch Antenna Pcb Design' title='Patch Antenna Pcb Design' />Wellshow Precision Inc. Wellshow Technology Co. Ltd., Manufacturing RF Connector, Coaxial Cable Assembly, Wifi, GSM, GPS Antenna. M2M/wp-content/uploads/2014/04/LTE-antenna-embedded-eval-board-400x311.jpg' alt='Patch Antenna Pcb Design' title='Patch Antenna Pcb Design' />Antenna Simulation in LTspice Electronics Forums. Youll be much better off simply using the conventional radio approachthan trying to simulate everything, especially when circuit equivalentsare nebulous like this. After all, if you cant quite tell what it shouldlook like, how wouldyou know if you could implement your model once youve found asatisfactory result What kind of antenna are you looking at, loop The first thing to knowabout a loop is, if its a very small loop Im guessing, at thisfrequency, it is, its radiation resistance is very low, meaning, you cantreat it as a nearly pure inductance Q 1. I think is typical, and itsbandwidth even with a matched load will be correspondingly narrow. The nature of the incoming signal could be modeled as a voltage or currentsource how doesnt really matter, because it isnt really either, its apower source that couples in. Again, you dont have voltage withoutcurrent and vice versa, its all about power flow, and the matching thatallows the power to flow. Since the loop is inductive, your first priority is to resonate it with acapacitor at the desired frequency. This will require a very precisevalue, and even for a single frequency, may require a variable capacitorto account for manufacturing tolerances. In the AM BCB, a Q of 1. Hz bandwidth, so you only get a few channels for any giventuning position. The G4ILO Wonder Loop is an easy to make compact portable magnetic loop antenna that covers 7MHz to 21MHz. You can make worldwide contacts using low power with an antenna. Customization Antenna Product Line AntennaConnectorCable Assembly Con Series Connector Options MCX, MMCX, MMC Specification Impedance 50 ohm. International discussion forum on EDA, circuits, electronics design, service manuals and related subjects. And if the Q is higher, you get even fewer. The Incredibles 2 Full Movie Download In Hindi more. Now that youve got a high Q resonant tank, you can do two things coupleinto the voltage across the capacitor, or the current through theinductor. You need only a small fraction of either, because the Q isstill going to be large. Our latest mechanical design was even smaller than earlier ones, and the battery was in front of the PCB, so we could no longer use a Bluetooth chip antenna. References 1. Microstrip Antenna Design Handbook Garg, Bhartia, Bahl, Ittipiboon 2. Antenna Theory and Microstrip Antennas Fang 3. CAD of Microstrip Antennas for. The most common type of microstrip antenna is the patch antenna. Antennas using patches as constitutive elements in an array are also possible. Unictron manufactures antennas NFC, subgiga frequencies, WiFiBluetooth, GPSGlonass internalexternal and ultrasonic elements. Just ask us, we have it. This can be arranged with a voltage dividerusually the capacitor is split into a huge hunk and a small variablepart, e. F variable 1. 0n. Over on our store weve recently released our new receive only dipole antenna kit which now replaces the older magnetic whip style antennas from the previous kit. F, output from across the 1. F, atransformer a potential transformer across the cap, or a currenttransformer in series with the inductor, an inductive pickup the bigloop carries lots of volts, but you only need a few, so a much smallerloop can be placed inside the big loop, an impractically large inductorlike in my example circuit, which models radiation resistance as aparallel equivalent, etc. Whatever the case, you need to matchtransmission line impedance e. Once you get the signal into a transmission line, with a reasonable matchZ Zline, or alternately, SWR 1, you can do whatever you want withit. Put it into an amplifier dont forget to match it, too, etc. Yes,youre going to have funny behavior at other frequencies, and if youreconcerned about those frequencies, youll have to choose the couplingcircuit and adjustable or selectable components accordingly. But forthe most part, you completely ignore any frequency that you arent tuningfor, usually enforcing that concept by inserting filters to reject anystragglers. Example suppose you have a loop of 5u. H and need to tune it to 5. Hz. Ithas a reactance of 1. Suppose further it has Q 2. The ESRnot counting DCR and skin effect is XL Q, or 0. EPR is XL Q, or 3. The capacitor required is 2. F. If weuse a current transformer to match to a 5. If we use a voltage transformer,its of course 8 1. A capacitor divider is unsuitable for resonantimpedances less than line impedance, since it can only divide theimpedance down. If the inductance were a lot larger, it could be used. To a rough approximation, a smaller inductive loop, of 18 diameter of thelarger, I think, would also work. Tim Deep Friar a very philosophical monk. Website http seventransistorlabs. On 22. 82. 01. 3 6 4. PM, Tim Williams wrote rickmanlt wrote in message news kgoo. A higher frequency would imply a smaller L andor C. How do you combine them to produce that Consider the two caps to be in series Sure. If you bring the 1. I dont have it in front of me now, in parallel with the primary. I misspoke earlier, you can safely ignore Ls, because k 1. Theres no flux which is not common to both windings. Reflecting the capacitance through the transformer changes it by the square of the turns ratio assuming the coupling coefficient is sufficiently high. I am simulating K at 1. This is also true for the inductance, but in the opposite manner. So going from the 2. In fact, in LTspice you indicate the turns ratio by setting the inductance of the two coils by this ratio. I see now that the reflected secondary capacitance is in parallel with the primary, rather than in parallel with the primary capacitor. That explains a lot. Ill have to hit the books to see how to calculate this new arrangement. I found a very similar circuit in the Radiotron Designers Handbook. In section 4. 6ivE on page 1. It need to be placed inline with the inductor. Ill have to cogitate on that a bit. Im thinking it would be properly placed inline with the capacitor in the reflection since it is essentially inline in the secondary. Either way I expect it will have little impact on the resonant frequency and I can just toss all the resistances simplifying the math. I do see one thing immediately. The null in Vcap I see is explained by the parallel resonance of the secondary cap with the secondary inductor. If you reflect that cap back to the primary in parallel with the primary inductor resonating at the same frequency it explains the null in the capacitor C1 voltage I see. C2 reflected and L1 make a parallel resonance with a high impedance dropping the primary cap current and voltage to a null. This null is calculated accurately. What I need to do is change the impedance equation from Radiotron to one indicating the voltage at Vout relative to the input signal. I think I can do that by treating the circuit as a voltage divider taking the ratio of the impedance at the input versus the impedance at the primary coil. No Inductors effectively in parallel also increase the expected resonant frequency. If you have this,. L1. UUU. Vsrc C R 3 L2. GND You might expect the resonant frequency is L2 C, but its actually L1 L2 Leq. If L1 is not substantially larger than L2, the resonant frequency will be pulled higher. I see, L1 and L2 are in parallel because the impedance of Vsrc is very low. That is not the circuit I am simulating however. The loop of the antenna and the loop of the inductor are in series along with the primary capacitor. Im not sure what the resistor is intended to represent, perhaps transformer losses The resistance of L1 was added to the simulation model along with the resistance of the secondary coil which you have not shown. I think. It seems to me you have left out the tuning capacitor on the primary. Incidentally, dont forget to include loss components. I didnt see any explict R on the schematic. I didnt check if you set the LTSpice default parasitic ESR cap, or DCR or EPR coil on the components.