Design of Low-Loss Microstrip Circulator Based on NiCuZn Ferrite Material

Microstrip circulators, due to their compact structure, small size, low cost, high degree of integration, stable performance, and good compatibility, have been widely used in microwave systems. To meet these requirements, higher performance standards are also demanded for the key material, NiCuZn ferrite, which should possess high saturation magnetization, narrow ferromagnetic resonance linewidth, and low dielectric loss, among other excellent properties. The narrow ferromagnetic resonance linewidth is crucial for effectively reducing the insertion loss of the device. This paper proposes and designs a low-loss microstrip circulator based on NiCuZn ferrite material, aiming to achieve a high-performance, low insertion loss, and good isolation microwave passive device. Through theoretical analysis, a microstrip circulator model operating at X-band frequencies was completed, and the design was verified using electromagnetic simulation software. The simulation indicated that at the center frequency of 10 GHz, the isolation is greater than 30.92 dB, the return loss is greater than 29.24 dB, the insertion loss is less than 0.33 dB, and the voltage standing wave ratio (VSWR) is less than 1.10. The performance of the designed circulator fully complies with the development direction of microwave communication equipment, which requires low loss, wide bandwidth, and high isolation. This validates its potential application in wireless communication and radar systems.