Conical Inductors


Application Notes > Custom Inductors > Conical Inductors

What are broadband conical inductor?

Gowanda’s off-the-shelf “flying lead” (FL) and surface mount (SM) broadband conical inductors are a special type of broadband RF choke that are used to filter radio frequency (RF) and microwave frequency interference from electronic circuits. At high frequency, the RF choke becomes a high impedance element used to isolate noise or DC from desired signals.

How does a conical inductor function?

An inductor placed in series (in line) with a wire or circuit board trade will impede changes in current, such as AC noise current, by temporarily storing energy in a magnetic field and then releasing it back into the circuit. As current through the inductor changes over time (di/dt) the energy stored in the magnetic field of the inductor creates a voltage (V = L * di/dt) that opposes (impedes) a further change in the current. Regardless of whether the current through the inductor is increasing or decreasing, the magnetic field slows the current’s rate of change. Similar to mechanical energy being damped by a shock absorber, the electrical energy of a noise current “spike” in an RF choke is dispersed over time to reduce its impact. Conical inductors provide high impedance over a very wide range of frequencies.

Why does the inductor have a conical shape?

The conical shape limits the effects of stray capacitance and effectively creates a series of narrow band inductors, resulting in high impedance over a very wide bandwidth. A single conical inductor can replace a series of many narrow band inductors. The unique conical construction offers predictable frequency response and repeatable RF performance. The unique broadband response of the coil is attributed to its precision winding, wire selection and coil configuration.

Isolating RF signals from a DC bias / broadband filtering

A broadband (wideband) conical bias choke placed in line with the DC bias of an amplifier blocks a wide range of high frequencies from reaching the DC source. In this way, the bias choke injects the DC bias while isolating the AC signal from distortion by any stray AC noise. The critical determination when choosing an RF choke for a bias tee is the frequency range that needs to be blocked. Other key parameters are DC resistance, current requirements, size and cost.

Benefits of Gowanda’s Conical Inductors:

Gowanda’s flying lead (thru-hole) and Surface Mount broadband conical inductors offer predictable frequency response and repeatable performance from 40 MHz to 50+ GHz with current ratings up to 10 Amps and <1% TML & <0.10 CVCM per ASTM E595 outgassing test. These conicals are specifically designed for high frequency applications where ultra-low insertion loss and return loss are design requirements. Their unique construction helps to limit the effects causes by stray capacitance. Reliability to M83446D, up-screening capability to MIL-STD-981, unique footprints and both standard & custom design options enhance utility.

Surface Mount

  • Proprietary mechanical mounting system to deliver consistent part-to-part performance.
  • Four physical size configurations to choose from
  • C100SM: this series offers designers a right or left mounting configuration to help address EMI concerns

Flying Lead

  • Nine physical size configurations to choose from
  • Four configurations are high current designs with up to 10 Amp rating


  • Broadband Chip Manufacturing
  • Communication Platforms
  • Communication applications for bias T’s (filter signals, remove noise)
  • High Frequency
  • Microwave Circuitry
  • RF Test Set-Ups
  • Test & Measurement
  • Test Gear
  • Test Instrumentation
  • Transmission Amplifiers

Flying Lead

Current Rating
C050FL0.28 – 0.470.45 – 0.87275 – 280
C070FL0.165 – 1.0500.080 – 1.50150 – 625
C100FL0.26 – 1.540.10 – 2.70110 – 573
C102FL0.47 – 3.8 0.19 – 3.70182 – 815
C182FL 1.47 – 10.7 0.33 – 7.10150 – 694
C225FL0.60 – 8.00.16 – 6.4089 – 562
C305FL0.30 – 1.00.020 – 0.1251300 – 7200
C550FL1.20 – 6.800.020 – 0.1252200 – 10500
C750FL2.50 – 160.020 – 0.2652200 – 8100
C1000FL5.0 – 220.030 – 0.2152700 – 7700

Surface Mount

Series Inductance µH DCR Ohms Current Rating mA DC
C070SM  0.165 – 1.050 0.080 – 1.50 150 – 625
C100SMNL 0.26 – 1.54 0.10 – 2.70 126 – 655
C100SMNR 0.26 – 1.54 0.10 – 270 126 – 655
C102SM  0.47 – 3.8  0.19 – 3.70 182 – 815
 C182SM  1.47 – 10.7  0.33 – 7.10  150 – 694
C225SM 0.60 – 8.0 0.16 – 6.40 93 – 589

Custom Products

Gowanda welcomes the opportunity to assist its customers with application-specific designs for a particular application where the requirements can not be met by off-the-shelf components.

Our capabilities in design, development, production and testing are extensive. If you are interested in custom products please contact us for assistance.