Frequently Asked Questions

What does a coil do for the RF circuit card?

Air coils are the simplest inductors. These are solenoidal coils that use an air core and can have a single wind of wire to a large number of turns depending upon the range of frequency they are designed for. These inductors have low nominal values of inductance but offer a high- quality factor. As there is no magnetic core, they do not suffer from operating losses due to the hysteresis, eddy current, or distortion common in magnetic cores. Because non-magnetic cores do not easily heat up when the high current flows through the coil, these inductors have a high Q-factor as there is minimal loss of energy by the core in the form of heat. As the frequency of the signal increases, the value of required inductance decreases, making air coil inductors suitable for high-frequency applications. The circuits processing ultra-high frequency usually needs air coils with a single turn.

What specifications are engineers looking for when selecting a coil?

In most cases, the Design Engineer has already calculated the value of the inductor required for the specific application. He or she provides the value, typically in nH (nano) or μH (micro) Henry. Other parameters which may or may not be known by the design Engineer are:

Wire material – This is usually driven by the bonding method being used by the customer
Insulated or bare wire
Spaces between the winds or not – Spaced coils allow for some tuning at installation
If not spaced winds bonded or not bonded – Bonded coils are mechanically stronger and are easier to handle
Some additional requirements could be height or length restrictions or maximum current required

Once agreed specifications are agreed upon MCI will build a sample lot of 6 pieces and provide to the customer to make sure the part performs as required in the next assembly. Lead time for samples is typically 1 week.

What / how does an engineer determine when to use multiple coils or additional turns?

The value of the coil depends on the circuit and application. Each application most likely
will require a different value or different coil type. MCI manufactures coils with spacing in
between the turns. This provides the user some flexibility in “tuning” the device. This tuning does not greatly change the inductance of the coil, but it can assist the Engineer in dialing in the circuit.

Are there limitations how many turns and diameter of coils one can specify? What impact does the tighter the diameter cause? Wire diameter? Number of turns?

The best answer is YES. The total amount of turns will depend upon several factors,
including wire type and diameter. MCI manufactures a range of coils that have 1 to 100 turns. MCI products span an inductance range of 1 nH to 1000nH. Wire type, turns, diameter (inner and wire) all impact the inductance of the coil. For example:

The greater the inside coil diameter of the windings, the greater the inductance
The smaller diameter wire, the greater the inductance
The greater number of turns in the coil, the greater the inductance

Material selection and composition? Can the engineer change the materials of a coil to affect the performance? What is affected and by how much?

Changing the material of the wire (Silver, Gold, Copper, Aluminum, etc.) will impact the inductance. Normally the wire type is chosen for cost and mounting requirements. This is usually done in conversations with MCI.

Can coils be surface mounted to a PCB?

MCI coils are axial lead and can be used in multiple applications (thru hole, Stripline, microstrip, etc.). MCI coils are primarily surface mounted, but the coils are not conducive to automated pick and place due to their cylindrical shape.

How can one tell that a coil is not performing the task intended?

The performance of the circuit will be impacted if the wrong value coil is used.

Can coils be re-used?

Coils are passive devices and can be soldered, unsoldered and resoldered. The miniature air coils are very small, and care needs to be used when installing or removing the devices.

Selling against packaged coil?

Packaged coils are used for different applications and are very inexpensive. Pennies verses dollars: however, the packaged parts do not have the Q rating necessary to perform in the circuitry in which MCI products are utilized.

How does MCI Coil differentiate from competitors?

MCI only produces miniature air coils. Many of our competitors offer a broader product offering. MCI is able to manufacture the difficult coils, in the quantities our customers require, that our competitors either cannot or will not build. Customers have stated that MCI’s lead time, on time delivery and quality, along with our ability to make small lots of difficult coils, more than compensate for a slightly higher price. MCI is typically the lowest cost solution for our customers miniature air coil requirements.

What questions should we be asking in our prospecting efforts for coil opportunities?

Does the customer have a need for RF and Microwave, high Q, low loss inductors?

What applications/markets utilize coils?

Typically, the MCI products are used in Defense, Satellite, Radar, Comms, EW and any Hi- Rel applications. MCI has product on several aircraft, missile and satellite programs. In addition, MCI coils are used in ATE (Automatic Test Equipment) Amplifiers and Pre-amplifiers, as well as medical equipment.

What is the difference between Microwave Components, Inc. (MCI) and Microwave Components, LLC (MWC)?

MCI manufactures and sells miniature air coils. The private company was founded in 1978 and located in Dracut, MA. MWC is a Boutique Distributor of RF and Microwave products (components, cables, connectors, etc.). MWC is a wholly owned subsidiary of American Distributors, LLC. MCI and MWC are two separate companies, both servicing the RF and Microwave market. MWC is a franchised distributor of MCI coils.

QUESTIONS?

Call us directly with questions or to discuss application and specs with experts at MCI.

Call Us! 978-453-6016

MCI's Commitment to Our Customers

MCI prides itself on its absolute confidentiality in all that we do. All our work is custom designed to our clients’ specifications and applications and is kept confidential from drawing board to completion and beyond.

MCI recognizes the significant negative impact product obsolescence has on the Defense, Hi Rel and Space markets we support. MCI will NOT obsolete any part number for convenience or low/inactive status. As long as MCI can obtain the raw materials required to manufacture the part, MCI will continue to support our customers and supply every part in our extensive product portfolio.

Let us assist you with what you need.
Call 978-453-6016 or send us a message.