5 Questions to Ask a Microwave Filter Company

Designing and building RF filters and subsystems can be a complex process. The components selected will depend largely on the application of the microwave filter as well as the environmental conditions it’ll be required to operate in. This also impacts the design, shape, and size of the filter.

Often engineers need to make trade-offs to get the performance they require and this means determining the impact of selecting one type of design over another. With the many variables that go into designing RF filters and subsystems, engineers spend a great deal of time seeking out answers relating to different design specifications, delivery timelines, and cost.

Overall, engineers need a microwave filter company to help them find a solution that will result in a reliable, high-performing RF filter, even when it is a custom design. In this article, we highlight some of the most commonly asked questions of a microwave filter company, and how an experienced manufacturer should answer them.

1. How Can You Ensure Reliability for My High-Pressure Application’s Components?

Filters that operate in either the space, broadband, or military context usually require high-demand applications. High altitude, extreme temperatures, and long-range frequency requirements are examples of this. That’s partly why microwave filters in these applications are often also required to be compact and lightweight, but there are a number of competing parameters to work around.

If you ask this question to a filter manufacturer, they might explain how decreasing the size of an RF filter can make it more lightweight, but that may constrain other parameters like its power handling capabilities, selectivity, or insertion loss. To make an informed decision on whether the reduction in size is worthwhile, they need to know how much this will impact the filter’s performance.

Because there are so many variables, the only way to determine reliability in specific high demand applications is through rigorous testing of a filter design. For a microwave filter company, this testing takes different formats which may include the following:

• Temperature cycling determines the impact of variable temperatures on the device. 

• Vibration testing evaluates if high speeds have the potential to dislodge or damage components. 

• The purpose of burn-in testing is to identify and address early failures, ensuring long-term reliability.

• Leak testing evaluates the effectiveness of seals on a device.

• Frequency testing confirms that the filter operates effectively within the required range. 

Once these individual tests have been completed, final testing and inspections are conducted to ensure that nothing has been overlooked and that the filter operates according to specification.

2. How Will My Specific Application Requirements Be Met? 

It’s beneficial to know that a microwave filter company can take on specific application requirements to create a custom design. This is achieved by way of a partnership where engineers from your company collaborate closely with those of the microwave filter company.

This is to achieve a deep understanding of the application requirements as well as the reasoning behind the design. Making use of the collective expertise, teams can work through the mechanical designs and provide realistic quotes based on project timelines. This level of transparency is beneficial in that there are no hidden costs or other surprises that could negatively affect the project.

3. What are Your Typical Lead Times on Prototype Filters and Subsystems?

Before work can begin on developing a prototype, a partnership needs to be established including a signed contract. Once that is in place, it typically takes between 4 to 8 weeks to develop a prototype.

Note: In extreme circumstances, our RF engineers will do our best to meet and exceed your lead time estimations.

The more complex the design, and the more collaboration and testing required may place the process closer to 8 weeks to completion. Much will depend on the specific application required of both the subsystems or the RF filters. Using more standardized components in the design can help reduce cost and decrease the development time.

4. How is Packaging Customized for RF Filters or Subsystems?

When it comes to RF filter packaging, the general requirements are often for it to be smaller or more lightweight. But this miniaturization can introduce challenges such as thermal management, susceptibility to electromagnetic interference (EMI), and mechanical stresses, which can affect the filter's performance. Considerations include: the desired input/output required, topology, and size constraints, as well as the installation method.

Understanding the different types of packaging, as well as the pros and cons of each helps to narrow in your options for customized filters and subsystems. For example, filters that need to operate in extreme environments may need to be hermetically sealed to prevent moisture build-up or ingress.

Additionally, packaging options are not confined to a box shape. The two examples below highlight customizable alternatives:

• The geometry of Micro Strip or Co-planar Micro-Strip results in lower loss and improved isolation performance. This type of packaging is most commonly used to achieve higher performance transitions at higher frequencies. It’s typically built within a kovar housing with a non-hermetic EMI seal.

• Formed Lead is mostly used for larger metal packages that are surface-mounted. The filter will be placed inside a brass or aluminum housing which is then mounted with mechanical fasteners. There are options to have these filters hermetically sealed depending on the application.

Because designing custom subsystems and filters is open to many variables, it’s beneficial to have access to the industry knowledge of a microwave filter company to help you decide on the best packaging.

5. How is Q Microwave Leading Microwave Filter and Subsystem Design?

As technologies such as 5G continue to evolve, innovation in microwave filter and subsystem design will need to keep pace. This is especially true in the area of tunable microwave filters and subsystems.

Because Q Microwave serves commercial, space, and military customers, our team is always drawing on collective knowledge and innovating. Our RF engineers are continually seeking ways to improve lead times, packaging, and custom mechanical designs. It’s a core value at Q Microwave to strive towards excellence, finding ways to minimize the trade-offs to create subsystems and filters that are compact, reliable, and durable.

If you have additional questions you can read more about Q Microwave’s RF subsystems and integrated filter products. This page details the variety of subsystem products available for different applications including military and commercial needs. 

For more than 25 years the kickass team at Q Microwave has been a leader in creating RF filters and subsystems. Learn how we can help you complete your application assembly and more today!