Enhanced Double Negative Metamaterial Microstrip Antenna: Bandwidth, Gain Improvement, and Size Reduction for Radar Applications

A miniaturized end-fire microstrip patch antenna with enhanced bandwidth and high-gain characteristics is presented. The design uniquely integrates complementary circular split-ring resonators (CCSRRs) in the rectangular radiation patch and an optimized grid of crossed slots in the ground plane, generating a double-negative metamaterial (DNG-MTM) response. This innovative combination significantly improves antenna performance in terms of gain, bandwidth, and size. The antenna achieves a wide operating bandwidth from 3 GHz to 8.4 GHz, delivering an exceptional 90% fractional bandwidth, substantially outperforming conventional designs. A strategically positioned rectangular slot beneath the feed line mitigates bandwidth limitations at higher frequencies, further enhancing impedance matching. The compact design (28 mm $\times 34$ mm, or $0.28\lambda $ g $\times 0.33\lambda $ g, where $\lambda $ g is the guided wavelength at the lower edge of the frequency band) achieves a peak gain of 6.9 dBi, representing a major size reduction and gain enhancement compared to existing counterparts. The proposed antenna’s novel DNG-MTM structure, compact size, and high performance make it an ideal solution for C-band radar and mobile wireless communication systems. Simulated and measured results demonstrate good agreement, validating the effectiveness of the design and its advantages over current technologies.