RF Tools & Calculators

ACTIVE CALCULATOR

RF power ↔ ADC voltage

Sinusoidal voltage across a specified real, resistive input.

Delivered RF power

dBm

Peak-to-peak voltage across load

Vpp

Both values are editable. Vpp is across the specified load: between ADC pins for a differential load, or signal-to-return for single-ended.

Effective real input resistance

Ω

Datasheet Vpp limit (optional; same measurement convention)

Vpp

RMS voltage—

Peak voltage—

RMS current—

Delivered power—

Power display

Enter a datasheet Vpp limit to compare the calculated voltage.

Sinusoidal resistive load

V_{pp} = 2 \sqrt{2 P R}

P = \frac{{V_{rms}}^{2}}{R}

This computes power delivered to a real resistive load, not available source power. Mismatch, complex/variable ADC input impedance, AC coupling, common-mode, absolute maximum, operating full-scale and differential-versus-single-ended ratings need separate checks. The optional limit is a voltage comparison, not a device safety approval.

AT A GLANCE

50 Ω sine-wave examples

Vpp measured across an actual 50 Ω resistive load, not an unmatched ADC input.

dBm	mW	Vpp
−20	0.01	0.06325 V
0	1	0.63246 V
10	10	2 V
20	100	6.3246 V

These examples are not device-specific ADC limits. Enter the ADC's effective input resistance and a relevant datasheet voltage limit above.

ACTIVE CALCULATOR

Return loss, reflection & VSWR

Passive one-port quantities at the same RF reference plane.

Understand return loss ↗

Known quantity Return loss

dB

Return loss20 dB

Reflection magnitude0.1

VSWR1.222222

Reflected incident power1%

Enter a valid return loss, reflection magnitude or VSWR.

Matched-reference, passive one-port

| Γ | = 10^{- \frac{RL}{20}}

VSWR = \frac{1 + | Γ |}{1 - | Γ |}

Use S11 for Port 1 or S22 for Port 2 at the appropriate frequency. The reflected percentage is relative to incident power at that port. “Not reflected” does not establish power transmitted to an ADC, antenna radiation efficiency or complex impedance; magnitude has no phase. VSWR here is defined only for a passive port with |Γ| ≤ 1.

AT A GLANCE

Reflection quick table

Ideal passive-port reference values; all quantities at the same frequency.

RL	\|Γ\|	VSWR	Reflected
0 dB	1	∞	100%
6 dB	0.5012	3.0095	25.12%
10 dB	0.3162	1.92495	10%
20 dB	0.1	1.22222	1%
30 dB	0.03162	1.06531	0.1%

Matched reference Γ = 0 gives VSWR = 1 and infinite return loss. Total reflection Γ = 1 gives VSWR = ∞ and return loss = 0 dB.

ACTIVE CALCULATOR

Complex impedance ↔ reflection coefficient

Phase-aware conversion at one RF reference plane with a real positive reference impedance.

Smith chart & impedance ↗

Known quantity Reference impedance Z₀

Ω

Resistance R

Ω

Reactance X

Ω

Resistance—

Reactance—

Complex Γ—

|Γ|—

Γ phase—

Return loss—

VSWR—

Reflected incident power—

Enter a passive complex impedance or reflection coefficient.

Real positive Z₀

Γ = \frac{Z - Z_{0}}{Z + Z_{0}}

Z = Z_{0} \frac{1 + Γ}{1 - Γ}

This is a reference-plane conversion for a passive one-port. It does not synthesize a matching network and does not establish antenna radiation efficiency, gain, bandwidth or link performance. Return-loss magnitude alone cannot recover impedance because Γ phase is required.

AT A GLANCE

50 Ω reference examples

Same reference plane and real Z₀ = 50 Ω.

Z	Γ	RL
50 + j0 Ω	0	∞
75 + j0 Ω	0.2 ∠ 0°	13.98 dB
25 + j0 Ω	0.3333 ∠ 180°	9.54 dB
0 + j50 Ω	1 ∠ 90°	0 dB

Purely reactive passive loads sit on |Γ| = 1. A perfect match sits at Γ = 0. The ideal open Γ = 1 ∠ 0° has infinite impedance.

ACTIVE CALCULATOR

Quick Match · ideal L network

Single-frequency lossless synthesis from a passive complex load to a real target resistance.

Understand Quick Match ↗

Load resistance R

Ω

Load reactance X

Ω

Target resistance

Ω

Frequency

MHz

Enter a passive load and a real positive target resistance.

Load → source orientation

Z^{'} = Z + j X

Y^{'} = \frac{1}{Z} + j B

Calculated · ideal single-frequency model. Candidate values assume lossless L/C elements at the entered frequency. This tool does not establish bandwidth, Q/ESR, tolerance, package/layout parasitics, power handling, antenna radiation efficiency, gain, pattern or range. Candidates are alternatives, not a ranked “best” design.

ACTIVE CALCULATOR

Frequency ↔ wavelength

RF wavelength in free space and a specified uniform medium.

Wavelength and velocity factor ↗

Frequency

MHz

Wavelength in medium

m

Both fields are editable. Changing velocity factor preserves the most recently edited quantity.

Velocity factor · fraction of vacuum light speed

× c

Free-space wavelength—

Half wavelength in medium—

Quarter wavelength in medium—

Period—

Propagation delay—

Phase velocity—

Uniform, nondispersive line approximation

λ_{0} = \frac{c}{f}

λ = VF λ_{0}

c = 299792458 m/s

Physical quarter-wave lengths vary with dielectric, connector, fringe effects and dispersion. Velocity factor here is the phase-velocity ratio for a uniform, nondispersive approximation (10⁻⁶ ≤ VF ≤ 1 in this calculator). Group delay and actual trace length need the appropriate line model and data at frequency.

AT A GLANCE

Free-space wavelength

Set VF = 1 for vacuum/free space. Lengths below are exact SI c divided by frequency, rounded for display.

Frequency	λ₀	λ₀/4
10 MHz	29.979 m	7.495 m
100 MHz	2.998 m	0.749 m
1 GHz	0.2998 m	74.95 mm
10 GHz	29.98 mm	7.495 mm

For a medium with VF = 0.66, multiply each free-space length by 0.66. This is not a substitute for the PCB stackup or cable datasheet.

ACTIVE CALCULATOR

Reactance ↔ L/C

Ideal inductor or capacitor reactance at one frequency.

See L/C in Quick Match ↗

Component type Frequency

MHz

Inductance

nH

⇄

Reactance X

Ω

Both fields are editable. Inductive reactance is positive; capacitive reactance is negative. Component input uses nH for L and pF for C.

Inductor · positive reactance10 nH

Ideal reactance62.83185 Ω

1000 MHz · 10 nH gives 62.83185 Ω in the ideal single-frequency model.

Ideal lossless element

X_{L} = 2 π f L

Calculated · ideal single-frequency model. This conversion does not include Q/ESR, package or layout parasitics, self-resonance, tolerance, temperature, power handling, bandwidth or component availability. A real part may stop behaving like an ideal L or C well before the entered frequency.

AT A GLANCE

Ideal examples

Signs follow the impedance convention Z = R + jX.

Frequency	Component	X
100 MHz	10 nH	+6.283 Ω
1 GHz	10 nH	+62.832 Ω
100 MHz	10 pF	−159.155 Ω
1 GHz	10 pF	−15.915 Ω

These are ideal values only. Check the actual component model, Q/ESR, self-resonant frequency and package/layout behavior before using a physical part.

ACTIVE CALCULATOR

Ideal LC resonance

Solve one ideal resonance quantity from the other two.

L/C context in Quick Match ↗

Solve for

Choose the unknown explicitly; the solved field is read-only.

Resonant frequency f₀

MHz

Inductance L

nH

Capacitance C

pF

Ideal resonant frequency159.1549 MHz

Inductance100 nH

Capacitance10 pF

100 nH with 10 pF resonates at 159.1549 MHz in the ideal lossless model.

Ideal LC resonance

f_{0} = \frac{1}{2 π \sqrt{L C}}

Calculated · ideal lossless model. This does not establish loaded or unloaded Q, ESR, damping, topology loading, bandwidth, tolerance, temperature, package/PCB parasitics, self-resonance, coupling, power handling or component availability. Real parts can depart substantially from this result near their self-resonant frequencies.

AT A GLANCE

Ideal resonance examples

SI equation, rounded only for display.

L	C	f₀
1 µH	1 nF	5.033 MHz
100 nH	10 pF	159.155 MHz
10 nH	1 pF	1.59155 GHz

A mathematical LC resonance is not a promise that the selected physical components remain ideal at that frequency. Check component models and self-resonant frequency.

ACTIVE CALCULATOR

Amplitude ratio

dB ↔ voltage, current or power-wave amplitude ratio

Learn more ↗

Decibels

dB

⇄

Amplitude ratio

×

Both fields are editable. Change either value to convert in the other direction.

Formula

D_{dB} = 20 \log_{10} | \frac{A_{2}}{A_{1}} |

D_{dB} = 10 \log_{10} (\frac{P_{2}}{P_{1}})

P_{dBm} = 10 \log_{10} (\frac{P}{1 mW})

−6.02 dB corresponds to approximately half the amplitude and one quarter of the corresponding power under equal real reference impedances.

AT A GLANCE

Quick reference

Common amplitude and power ratios for the same decibel values.

dB	Amplitude	Power

Power uses 10 log₁₀. Amplitude uses 20 log₁₀. For the same dB value, the power ratio is the amplitude ratio squared.

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