In this paper, a novel shaped patch antenna for triple band frequency of operation in X-band (radar) is defined. The antenna resonates under three frequency bands at 10 GHz, 10.93 GHz and 11.68 GHz respectively which are included in the X-band frequency range. The substrate material used as the dielectric between the patch and the ground is of Flame Retardant Version 4 (FR4) Epoxy. The DGS (Defected Ground Structure), usually included in the back conductor of the Microstrip patch antenna is used to tune the frequency and also to boost the characteristics of the antenna. The same is included in this depicted antenna with circular ring shaped slot to vary the performance. FEM (Finite Element Method) based Ansoft High Frequency Structural Simulator (HFSS) V.12 is used for designing and verifying the features of the proposed antenna. The size of the depicted model on the whole is of 31.34 × 28.33 × 1.6 mm3. For the first, second and third resonant frequency, a bandwidth of 480 MHz, 600 MHz and 420 MHz correspondingly is obtained with a return loss value of -18.47 dB, -42.22 dB and -19.74 dB. The other parameters of the antenna are also conferred in this paper.

The design of a double layer stacked microstrip loop shaped patch antenna for multiband operation has been proposed. The design has been evolved following the iterations of a rectangular patch and a single layer loop patch structure. The material considered for the substrate of both the layers is 1.6 mm thick FR4 epoxy and the feeding technique used for the bottom patch is coaxial/ probe feed. The radiations from the bottom layer patch have been electromagnetically coupled to the upper layer patch. The main results including the reflection coefficient, bandwidth, radiation pattern, gain, directivity and VSWR for single frequency operation in each case have been discussed separately and finally compared. The comparison shows that the proposed stacked structure is clearly advantageous over the conventional rectangular patch and the single layer designed prototype in terms of the standard parameters that have been obtained. The three stage designs are useful to serve the X-band aviation applications including radio location and fixed mobile radio location.