Thermal Drift in a Microwave Cavity Filter
Application ID: 692
Microwave filters are used to eliminate unwanted frequency components in the output from microwave transmitters. They are typically inserted between a power amplifier and an antenna. The amplifiers are nonlinear and produce harmonics that must be eliminated with filters that have a rather narrow passband.
Due to high power loads but also possibly from harsh environmental conditions (such as a cellular base station sitting in the sunshine in Phoenix), it is necessary to estimate the drift of the passband frequency due to thermal expansion.
It is easy to demonstrate that by using steel for the cylinder, a temperature-driven adjustment of the distance between the cylinder end and the brass box (where the adjustment screw is) can automatically compensate for most of the thermal drift.
This model example illustrates applications of this type that would nominally be built using the following products:
however, additional products may be required to completely define and model it. Furthermore, this example may also be defined and modeled using components from the following product combinations:
- COMSOL Multiphysics® and
- RFモジュール and
- either the MEMS モジュール, 金属プロセスモジュール, or 構造力学モジュール and
- either the 音響モジュール, MEMS モジュール, マルチボディダイナミクスモジュール, or 構造力学モジュール
The combination of COMSOL® products required to model your application depends on several factors and may include boundary conditions, material properties, physics interfaces, and part libraries. Particular functionality may be common to several products. To determine the right combination of products for your modeling needs, review the 製品仕様一覧 and make use of a free evaluation license. The COMSOL Sales and Support teams are available for answering any questions you may have regarding this.