Dual-frequency Microstrip Antenna Loaded with DPS-NIZ Waveguided Metamaterial

A stratified waveguided artificial metamaterial with partial double positive (DPS) property and partial near zero index (NIZ) property was developed. The two segments of such metamaterial are composed of embedded meander line (EML) cells and complementary split-ring resonator (CSRR) cells, respectively. The waveguided DPS-NIZ metamaterial was used as the equivalent substrate of microstrip patch antenna to achieve a dual-band operation characteristic. Theoretical analysis, simulation and experimental results show that the two lowest-order resonant modes of the dual-frequency antenna are TM010 and modified TM020 modes. The dual-frequency antenna has fairly consistent broadside radiation characteristic in the two operational bands. This antenna has the advantages of compactness and ease of fabrication with normal printed circuit board (PCB) process.