## 4 Heterogeneous Substrate and Analysis  
Microstrip antennas are often made on a homogeneous substrate and are low-profile, conformal, lightweight, and compact in size. By using a dielectric with a high permittivity value, the size of the antenna can be easily reduced. The energy in the surface wave modes is raised by this rise in dielectric though. Because they are diffracted via the margins of the ground plane of finite size, these surface waves decrease the performance and efficiency of the antenna and cause interference with the radiation pattern. These negative effects might be minimized by the reductions in surface wave modes. The main cause of surface wave radiation for thin-substrate microstrip antennas is unquestionably the TM0 mode, and heterogeneous substrates provide the solution to nearly completely suppress all of the surface waves inspired by this mode. The substrate surrounding the patch is simply removed, either completely or partially, to create heterogeneous substrates. By suppressing the surface waves, this method has \begin{table}
\begin{tabular}{c c c c} \hline
**SL** & **10** & **Lr** & **0.6** \\ \hline SW & 10.7 & Wr & 2.2 \\ \hline Ld & 1.6 & S1 & 0.2 \\ \hline Wd & 1.6 & S2 & 1.3 \\ \hline Ld1 = Ld2 & 1.53 & G & 0.08 \\ \hline Wd1 = Wd2 & 1.1 & h & 0.11 \\ \hline \end{tabular}
\end{table} 
Table 1: Description of elements for designing antenna in mm. Figure 3: Schematic view of antenna design. been utilized to boost the gain of a microstrip antenna. The antenna has also undergone substrate removal, which has significantly improved bandwidth and efficiency. Therefore, higher gain, bandwidth, and efficiency are due to the heterogeneous substrate, as mentioned in Figure 4. The designed with heterogeneous substrate (Figure 4a) has a radiation efficiency of \(-0.2737\) dB and total efficiency of \(-0.3851\)dB. The design without heterogeneous substrate (Figure 4b) has a radiation efficiency of \(-0.3673\) dB and total efficiency of \(-0.7626\) dB. The design with heterogeneous substrate is more efficient as compared with the plain substrate. The patch traces and the piece that was removed from the substrate are an exact match. Prior to the invention of 3D printers, it was impossible to produce this kind of substrate, but now it is possible to precisely construct heterogeneous substrates. Figure 5 compares the outcomes of the proposed model based on it with and without heterogeneous substrate. The horizontal axis is associated with the frequency range, while the vertical axis is maximum gain on the specific frequency. The without heterogeneous substrate model has a max. gain of 10.2 and varies sharply with an increase or decrease in frequency, while the design with heterogeneous substrate has a max. gain of 11.8 and is quite stable as compared with the design without heterogeneous substrate. Figure 4: Rad. and tot. efficiency: (**a**) with heterogeneous substrate and (**b**) without heterogeneous substrate. The gaps in the element which separates every specific component, irrespective of whether it is on the x-axis or even the y-axis, execute a vital function in the layout. The gap 'g,' which is undoubtedly on the x-axis, is the gap among all the individual elements along the identical x-axis. This distance is accountable regarding mutual coupling among driven elements and parasitic elements. Due to their shorter length than the driven element, the D1 elements (D1T and D1B) are actually in charge of obtaining beam directionality and producing an additional band at a higher frequency. S1 and S2, which represent the gaps between Top Directors and Bottom Directors and are located along the y-axis, are typically in charge of improving. To obtain the strong coupling between the Driven and Director 1 elements, the S1 parameter needs to be small. The distance between the director and driven components must be kept as short as feasible in order to put the parasitic elements next to the driven elements. The gap capacitance will decrease as the electric field coupling increases.