Analysis and design of compact planar crossover

Compact planar crossovers with single and dual band application are proposed. The crossovers are derived from the conventional two-section branch-line crossover by equivalent quarter-wavelength transmission-line with stubs, which reduces the circuit size and complexity. The crossover geometries and design procedure are discussed in detail according to the derived formulas. For verification, a single-band crossover working at 2.4 GHz and a dual-band crossover applied at 2.2/3.4 GHz are fabricated and tested. The proposed crossovers feature planar implementation with moderate line impedance, compact size and good performance. Both simulated and measured results are consistent with each other.