Custom Antenna Design

There are multiple benefits for choosing a custom antenna:

Cost
In the case of PCB antennas, a trace antenna can save a significant amount of cost over a chip antenna during the entire production run of your product. Other reasons like combining frequency bands to save on the number of antennas or customizing a radiation pattern to cover a specific application can have significant cost savings for your project.

Flexibility
A specific set of requirements can be discussed for a product’s application to provide peak antenna performance. This allows for greater flexibility with the assurance that the antenna will perform as needed without any surprises.

Expertise
An antenna specialist can guide your company to a wireless solution by providing options that work for your application.

Connector types vary based on the configuration requirements, but some typical configurations are as follows:
Antennas Modules
The most popular connector types for modules are SMA and MHF4 / U.Fl. This is due to their compact size, low return loss, and high frequency operation.

External Antennas
Outdoor antennas typically operate under harsh conditions and with higher power. N-type is by far the most widely accepted connector type for high power applications. TNC, BNC, and even SMA are also used for lower power or low frequency applications.

The duration of a custom antenna development project really depends on the requirements.

Generally, a simple antenna that’s close to an existing Commercial Off-the-Shelf (COTS) solution can have a relatively quick 6-12 week turn-around delivery.

Medium sized projects of around 20 weeks are typically for standard antenna architectures, but with more complex requirements like dual-band operation or specific uncommon requirements.

Large projects with electrical, mechanical, thermal, structural, and industrial engineering requirements could require 6-12 months depending on the qualifications needed for the antenna.

To get a better idea of the schedule required to deliver a custom antenna, it’s best to speak to an antenna design expert.

Some challenges antenna designers face when developing a new antenna solution:

• Selecting the right antenna architecture that will meet the product requirements
• Choosing a simulation software that will quick product the most accurate results and converge quickly on an optimized solution
• Conducting antenna tests that validate the antenna performance with respect to the given requirements

This obviously not an exhaustive list but at least provide some the top challenges to converge on a wireless solution.

Choosing the best antenna design software to develop an antenna depends on the type of antenna and how it is modelled. To design an antenna, the following solvers can be used:

• FEM (Finite Element Method) is used typically for feeds, horns, lens, pcb, and other types of antenna with hollow waveguide or different dielectric materials with more organic shapes. A commercial FEM option with years of vetted experience would be Ansys Electronics Desktop (HFSS).
• FDTD (Finite Difference Time Domain) is also used for feeds, horns, and pcb antennas, but the meshes are generally limited rectangular or cylindrical discontinuities due to how the FDTD mesh is generated. A good example of a well adopted FDTD solver is CST. OpenEMS is an open-source solution that is free to use.
• MoM/IE (Method of Moments or Integral Equation) is typically used for external antenna without dielectrics such as reflector dishes, monopoles, dipoles, yagi and other external antennas. FEKO is one of the most popular commercial antenna tools in this area of expertise. HFSS also has an IE solver with Domain Decomposition which helps solve electrically large antenna problems.

Choosing the right solver for your antenna design can save significant amounts of time and cost by converging quickly towards a solution for a set of specific requirements.

Aluminum is the preferred choice of metal when it comes to fabricating external antennas. Other than it being a light weight, it offers better conductivity than steel. This means higher gain (ie: lower loss) for the same power! It’s also very resistant to corrosion and has great thermal properties to route and dissipate heat. There are also metallic 3d printing options for more organically shaped antennas.

For the lowest loss and highest performance, Silver is used to plate surfaces and further improve electrical performance. Silver has the lowest loss of all the standard options, but requires additional processes and comes at a higher cost.

Copper is typically used in PCB modules due to its high conductivity and lower cost. Copper is especially useful in flexible and conformal antennas due to is malleable properties.

Gold plating is typically used on connectors or other interfaces for it’s improved mating/demating performance, but it should be noted that it is less conductive than Copper.

If enough power is applied to the antenna port, high power breakdown can occur by ionization of the gases making a conductive path between metallic surfaces. This can cause damage to the antenna metal surfaces or dielectric materials. Typically, large gaps will lower the electric field and the probability of breakdown, so wire antenna like helical, dipole, and monopole antennas will perform quite well at higher powers. Horns and waveguide arrays like a slot array also perform well at high power.