Co-design Structure of Dual-Band LNA and Dual-Band BPF for Radio Navigation Aid Application

In this paper, a co-design of a dual-band low-noise amplifier (DB-LNA) with a dual-band band-pass filter (DB-BPF) for a radio navigation aid (RNA) application was proposed. The novel development was that the DB-LNA was directly integrated with the DB-BPF instead of connecting the output matching network (OMN) of the DB-LNA to the 50 Ω-port of the DB-BPF. Thus, this DB-BPF had a double function, serving as the DB-BPF and also as the OMN. This architecture was called the co-design structure. Z_IN analysis was used to evaluate the co-design network structure. In general, the design procedure was divided into four sections, including (1) DB-BPF, (2) DB-LNA, (3) Cascade DB-LNA and DB-BPF, and (4) Co-design DB-LNA and DB-BPF. The co-design method was applied in an RNA implementation at dual-band frequencies of 113 MHz and 332 MHz. Validation of the proposed structure is confirmed for its accuracy by simulating the impedance characteristic Z_IN, S parameter simulation, and measurement results. The key contributions of this paper were that: (1) The co-design structure could reduce the passive component by 31.5%, (2) the total size of the DB-LNA and DB-BPF using the co-design method was smaller than the cascaded method by 11.36%, (3) more light-weight in fabrication due to a smaller size, and (4) finally, the proposed LNA has a higher figure of merit than the other LNA.