# Multifunction RF Systems for Naval Platforms
## 2 Requirements for Naval RF Functions
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \multirow{2}{*}{**RF Function**} & **Frequencies of Operation** & **Signal Bandwidth** & **Dynamic Range** & **EIRP (dBW)** & **One-Way Beamwidth** & **Duty Cycle (\%)** & **Signal Polarization** \\  & **(GHz) \({}^{*}\)** & **(MHz)** & **(dB)** & **(dB)** & **(deg)** & **(deg)** & **(deg)** \\ \hline Radar–volume search & L-band or & \multirow{2}{*}{2} & \multirow{2}{*}{90} & S-band: 90 & \multirow{2}{*}{2} & S-band: 95 & \multirow{2}{*}{2} & \multirow{2}{*}{20} & Linear (V) \\  & S-band or & & & L-band: 75 & & & & \\ Radar–horizon search & S-band & \multirow{2}{*}{5} & \multirow{2}{*}{90} & \multirow{2}{*}{90} & \multirow{2}{*}{2} & \multirow{2}{*}{20} & Linear (V) \\  & X-band & & & & & & \\ Radar–target & \multirow{2}{*}{X-band} & negligible & N/A & 90 & N/A & \(\leq\)100 & Linear (V) \\ illumination & \multirow{2}{*}{0.5–40} & \multirow{2}{*}{1000} & \multirow{2}{*}{60} & N/A & 1 & N/A & All \\ Electronic support & \multirow{2}{*}{0.5–40} & \multirow{2}{*}{1000} & \multirow{2}{*}{80} & \multirow{2}{*}{80} & \multirow{2}{*}{80} & \multirow{2}{*}{80} & \multirow{2}{*}{80} \\ Electronic attack & \multirow{2}{*}{0.5–40} & \multirow{2}{*}{1000} & \multirow{2}{*}{80} & \multirow{2}{*}{80} & \multirow{2}{*}{80} & \multirow{2}{*}{80} \\ Comms–X-band & & & & & & & Circular \\ SATCOM & \multirow{2}{*}{7.3–7.8 (Rx)} & \multirow{2}{*}{125} & \multirow{2}{*}{70} & \multirow{2}{*}{55} & \multirow{2}{*}{2} & \multirow{2}{*}{80} & \multirow{2}{*}{80} \\  & & & & & & & & \\ Comms–K\({}_{\text{u}}\)–band & \multirow{2}{*}{10.7–12.8 (Rx)} & \multirow{2}{*}{55} & \multirow{2}{*}{70} & \multirow{2}{*}{65} & \multirow{2}{*}{1} & \multirow{2}{*}{80} & \multirow{2}{*}{80} \\ SATCOM & \multirow{2}{*}{13.8–14.5 (Tx)} & \multirow{2}{*}{55} & \multirow{2}{*}{70} & \multirow{2}{*}{65} & \multirow{2}{*}{1} & \multirow{2}{*}{80} & \multirow{2}{*}{80} \\ Comms–K\({}_{\text{a}}\)–band & \multirow{2}{*}{19.2–21.2 (Rx)} & \multirow{2}{*}{125} & \multirow{2}{*}{70} & \multirow{2}{*}{65} & \multirow{2}{*}{0.5} & \multirow{2}{*}{80} \\ SATCOM & \multirow{2}{*}{29.0–31.0 (Tx)} & \multirow{2}{*}{125} & \multirow{2}{*}{70} & \multirow{2}{*}{65} & \multirow{2}{*}{0.5} & \multirow{2}{*}{80} \\ Comms–TCDL & \multirow{2}{*}{14.4–14.8 (Rx)} & \multirow{2}{*}{300 (Rx)} & \multirow{2}{*}{70} & \multirow{2}{*}{45} & \multirow{2}{*}{2} & \multirow{2}{*}{80} \\  & & \multirow{2}{*}{15.2–15.4 (Tx)} & \multirow{2}{*}{90 (Tx)} & \multirow{2}{*}{70} & \multirow{2}{*}{45} & \multirow{2}{*}{2} & \multirow{2}{*}{80} \\ \hline \end{tabular} \({}^{*}\) See more details on frequency band designations in Table 1.  
\end{table} 
Table 1: Comparison of transmit/receive requirements for naval RF functions. be so for the purposes of this table. Narrower beamwidths allow more accurate localization and tracking of detected targets for RF functions such as radar and ES, but slow down the scanning process in a given search volume. * _Duty cycle_: The duty cycle value in Table 1 is a characteristic of transmitted waveforms for those RF functions that involve signal transmission. It is calculated as \(\tau/T\) where \(\tau\) is the time duration of the transmitted waveform and \(T\) is the waveform repetition interval. * _Signal Polarization_: The signal polarization that must be accommodated upon transmit and/or receive has a significant impact on the design of the required radiating elements in the array. For signals with a single linear polarization, a relatively simple radiating element design can be used, whereas for any other signal polarization, a more complex dual orthogonally-polarized element design is needed. Note that in addition to the requirements listed in Table 1, there is a common requirement for all naval RF functions to provide full or almost full hemispherical coverage above the ship deck. Specific discussion of the requirements as they apply to the different RF functions is provided in the subsections below.