Abstract: Method of forming a high-performance, low-cost filter is provided. The filter comprises a housing and a cover. The housing defines a cavity in which one or more rods are disposed, one end of each rod being integrally formed with the housing. The rods function as coaxial resonators. A cover, disposed over the cavity, is securable to the housing. Input and output signal leads are coupled in conventional configurations to the rods. In one embodiment, the housing and cover are formed from a moldable dielectric material, such as plastic, which is then plated with a conductive film. In another embodiment, the housing is formed from a moldable dielectric material which is then plated with a conductive film while the cover is formed from a conductive material. The present invention provides optimal performance by using air as a dielectric separating the rods which function as coaxial resonators.