# Effect of Buildings on the Radiation Characteristics of MF Broadcast Antennas
## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Study** & **Frequency Range** & **Antenna Model** & **Building Model** & **Method** & **Purpose** & **Main Results-Conclusions** \\ \hline
[12] & MF (990 kHz) & T-type, 60 m in height & \(\lambda/4\) parasitic monopole or infinite-long PEC cylinder & Reciprocity or dyadic Green’s function technique & Impact of building on radiation pattern and field intensity & Decrease in field intensity up to 2.3 dB. The radiation pattern is mostly affected by the height of the building. & The reduction in field intensity around a building may be up to 4 dB (building 30 m high, 100 m from the antenna, while the field variation becomes negligible 400 m from the antenna. \\ \hline
[2] & HF (2-30 MHz) & Logical periodic dipole antenna (LPDA) & Rectangular parallelepiped (mesh of metallic wire segments and triangles) & Full-wave simulation software package (FEKO) & Impact of buildings on radiation pattern, gain, VSWR. & Only the radiation pattern (among gain, VSWR, impedance) is affected by building blockage. The impact on patterns is greater if the size of height blockage is larger than \(\lambda/2\). & The antenna response changes due to the presence of buildings, resulting in estimation error of the DF system (up to \(1^{\circ}\) for the azimuth and \(7^{\circ}\) for the elevation). & Only the radiation pattern (among gain, VSWR, impedance) is affected by building blockage. The impact on patterns is greater if the size of height blockage is larger than \(\lambda/2\). & The antenna response changes due to the presence of buildings, resulting in estimation error of the DF system (up to \(1^{\circ}\) for the azimuth and \(7^{\circ}\) for the elevation). & Only the radiation pattern is significant error of the DF system (up to \(1^{\circ}\) for the azimuth and \(7^{\circ}\) for the elevation). & The reduction of the direction of the principal radiation lobe and production of side lobes, depending on the distance between the antenna and the building and the permittivity and size of the building. \\ \hline
[6] & 2.45 GHz & Rectangular patch antenna & Complex wall structures & Commercially available software (CST Microwave Studio) & Impact of walls on the radiation characteristics of access-point antennas & The radiation pattern is distorted (compared to the free-space pattern) when the antenna is mounted on complex wall structures, especially corners. & The calculation results were calculated through measurements and the resonant characteristics of the building & The calculation results were calculated through building were determined. \\ \hline
[29] & 30 MHz–1 GHz & Electric dipole inside the building & Wire-grid body & MoM & Derivation of EM field distribution in and around buildings & The calculation results were measurements and the resonant characteristics of the building & The calculation results were determined. \\ \hline
[4] & 0.75-5 GHz & Horn antenna & Single solid-metal cylinder or a set of such cylinders & Numerical simulation (by using the tool) & Design of the appropriate cloak to reduce the blockage & The (uncloaked) objects produce strong sidelobes to the antenna’s radiation pattern (compared to free space) and decrease its directivity. & The (uncloaked) objects produce strong sidelobes to the antenna’s radiation pattern (compared to free space) and decrease its directivity. \\ \hline Current study & MF (1494 kHz \& 1008 kHz) & Monopole and 2-element array & Rectangular parallelepiped (wire-grid body) & Point-matching solution and custom computer code & Impact of buildings on radiation pattern & The (uncloaked) objects produce strong sidelobes to the antenna’s radiation pattern (compared to free space) and decrease its directivity. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparative synopsis of studies dealing with the effect of buildings on antenna radiation.