Solve coax and RLC impedance behavior accurately. Compare load matching, reflection, and resonance across frequencies. Get exports, formulas, examples, and charts for clearer analysis.
The graph sweeps frequency around your chosen center value. It plots impedance magnitude, VSWR, and reflection magnitude on one interactive chart.
| Mode | Frequency | Input Set | Computed Load Z | VSWR | Return Loss |
|---|---|---|---|---|---|
| Direct | 100.0000 MHz | Z = 45.0000 + j10.0000 Ω | 45.0000 + j10.0000 Ω | 1.2651 | 18.6332 dB |
| Series | 100.0000 MHz | R=42.0000 Ω, L=0.0800 µH, C=22.0000 pF | 42.0000 - j22.0777 Ω | 1.6603 | 12.1041 dB |
| Parallel | 145.0000 MHz | R=75.0000 Ω, L=0.1200 µH, C=8.0000 pF | 73.5708 + j10.2540 Ω | 1.5230 | 13.6679 dB |
| Direct | 433.9200 MHz | Z = 50.0000 + j0.0000 Ω | 50.0000 + j0.0000 Ω | 1.0000 | ∞ dB |
Series RLC load: Z = R + j(ωL − 1/ωC)
Parallel RLC load: Y = 1/R + j(ωC − 1/ωL), then Z = 1/Y
Angular frequency: ω = 2πf
Reflection coefficient: Γ = (ZL − 50) / (ZL + 50)
VSWR: VSWR = (1 + |Γ|) / (1 − |Γ|)
Return loss: RL = −20 log10(|Γ|)
Mismatch loss: ML = −10 log10(1 − |Γ|2)
Complex power: S = V × I* with I = V / Z
These relations idealize the network and focus on a 50 Ω reference. They are useful for quick design checks, matching studies, and RF troubleshooting.
Fifty ohms is a practical reference used in many RF systems because it balances power handling and loss reasonably well. When a load differs from 50 Ω, part of the signal reflects back toward the source. That reflection changes standing waves, return loss, and delivered power.
This calculator helps you inspect those effects quickly. You can test a direct measured impedance or build a load from RLC parts. The interactive graph also reveals how the match changes across frequency, which is useful when tuning resonant networks, antennas, filters, sensors, and transmission interfaces.
Because impedance is complex, a load can fail matching even when the resistance looks close to 50 Ω. The reactive part matters too. By watching the impedance magnitude, phase angle, and VSWR together, you can decide whether to retune component values, shift frequency, or add matching elements.
It compares your load against a 50 Ω reference. It reports impedance, reflection coefficient, VSWR, return loss, mismatch loss, current, and power quantities from the values you enter.
Use direct mode when you already know the real and imaginary parts of the load impedance from a network analyzer, simulation, datasheet, or measured equivalent circuit.
VSWR increases when the reflection coefficient approaches one. That happens when the load differs strongly from 50 Ω, so more energy reflects instead of transferring forward.
Series mode builds impedance directly from resistance and net reactance. Parallel mode builds admittance first, then converts it to impedance, which can produce very different matching behavior.
No. A perfect match also needs zero reactive part. A load of 50 + j20 Ω is not perfectly matched because the imaginary component still causes reflection.
Return loss expresses reflected signal level in decibels. Larger positive values usually indicate a better match because less power comes back from the load.
The graph shows how matching behavior changes across frequency. That makes it easier to spot resonance, narrow tuning windows, and frequency regions with acceptable impedance behavior.
They are useful for screening, estimation, and education. Final RF design should also consider distributed effects, parasitics, conductor loss, dielectric loss, temperature, and layout geometry.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.