Dual-Band Lumped-Element Bandpass Filter

In this study, a dual-band lumped-element bandpass filter (DBLEF) is presented, which is implemented in low-temperature co-fired ceramic. The design utilizes the tight component coupling possible in this technology to mimic a much more complex network of lumped components. The filter is unique in that it utilizes only a single set of lumped components to create a dual-passband response. Detailed design equations are presented for the dual-band design, and a DBLEF having passbands at 2.4 and 5.2 GHz is demonstrated, representing the common wireless local area network bands. This paper both introduces a novel approach to lumped-element dual-band filtering, while also demonstrating an effective method of implementing this complex filter in multilayer technology with a very small footprint. Both measured and simulated results verify the approach with the overall size of the filter only 154times135times22.8 mil³ (3.85times3.38times0.57 mm ³)