Planar Single/Dual-Band Crossovers With Large- Frequency Ratios Using Coupled Lines

Compact planar crossovers with large-frequency ratios using coupled lines for single-band and dual-band are proposed in this letter. Conventional coupled lines with different transmission lines are used to realize the single and dual passband. The center frequency of the single-band crossover and frequency ratio for the dual-band can be easily changed by changing the characteristic impedance of the coupled and transmission lines. Two compact planar crossovers located at 1.35 and 1.31/2.69 GHz are designed and measured. The measured results are in good agreement with the simulated ones.