# Effect of Buildings on the Radiation Characteristics of MF Broadcast Antennas
## 3 Results
### Radiation Patterns of the Monopole  
Indicative radiation patterns of the monopole in the presence of one or two buildings are plotted, herein, for different values of the parameters \(L\), \(W\), \(H\), and \(R\). The distance \(\Delta\) between two adjacent wire segments was taken to be equal to \(2.5\) m \(\approx 0.0125\lambda\).  
The patterns in Figures 4a and 5a refer to the \(\varphi\)-plane (at a specific value of \(\theta\), i.e., \(\theta=89^{\circ}\)), while Figures 4b and 5b depict the \(\theta\)-plane for \(\varphi=90^{\circ}\). The length \(L\) and the width \(W\) of the building (given in the inset) were kept constant in order to investigate the effect of the height \(H\) on the radiation pattern of the antenna; three different values of \(H\) were considered (given in the inset). Moreover, the impact of the distance between the antenna and the building on the radiation pattern was examined by considering two values of \(R\), i.e., \(R\) = 100 m (Figure 4) and \(R\) = 200 m (Figure 5). Both values indicate that the building was in the radiating near-field region of the antenna.  
Figure 4: Radiation patterns of the monopole in free space (black, solid curve) and in the presence of a building with \(L=10\) m \(\approx 0.05\lambda\) and \(W=10\) m \(\approx 0.05\lambda\). Three different heights \(H\) are considered (dashed and dotted curves, as indicated in the upper right corner). The distance between the antenna and the building is \(R=100\) m \(\approx 0.5\lambda\). (**a**) \(\varphi\)-plane and (**b**) \(\theta\)-plane.  
The influence of the building size on the radiation characteristics of the antenna was investigated through Figures 6 and 7. Figure 6 refers to a building \(60\times 10\times H\) m\({}^{3}\), i.e., it has the same width as the building considered in Figure 4, albeit it is six times longer. In Figure 7, the building is \(10\times 20\times H\) m\({}^{3}\), i.e., its length is kept the same as the building in Figure 4, albeit its width is six times greater.  
Figure 5: The same as Figure 4, except for the distance between the antenna and the building (\(R=200\) m \(\approx\lambda\)). (**a**) \(\varphi\)-plane and (**b**) \(\theta\)-plane.  
Figure 6: Radiation patterns of the monopole in free space (black, solid curve) and in the presence of a building with \(L=60\) m \(\approx 0.3\lambda\) and \(W=10\) m \(\approx 0.05\lambda\). Three different heights \(H\) are considered (dashed and dotted curves, as indicated at the upper right corner). The distance between the antenna and the building is \(R=100\) m \(\approx 0.5\lambda\). (**a**) \(\varphi\)-plane and (**b**) \(\theta\)-plane.  
Subsequently, two identical buildings were considered in the vicinity of the radiating antenna. The first was placed along the \(x\)-axis, whereas the second was along the \(y\)-axis. Each building was assumed to be 100 m (Figure 8a) or 200 m (Figure 8b) from the antenna. The patterns refer to the \(\theta\)-plane for \(\varphi=90^{\circ}\), while the \(\varphi\)-plane was omitted for the sake of brevity. The effect of the height \(H\) on the radiation pattern of the antenna was investigated by considering three different values of \(H\) (given in the inset).