Monostatic vs. Bistatic Radar: Key Differences Explained

This article explores the differences between monostatic and bistatic radar systems, outlining their key characteristics and functionalities.

Monostatic Radar

Overview

Monostatic radar is a type of radar system that uses the same antenna for both transmitting and receiving signals.

Block Diagram

Figure 1: Monostatic radar block diagram.

As shown in Figure 1, a duplexer is a crucial component in monostatic radar. It’s responsible for separating the transmit chain from the receive chain, allowing the single antenna to be used for both functions without interference.

Monostatic Radar Equation

The performance of a monostatic radar system can be described by the following equation:

Where:

• $P_R$ = Total power received at the receiving antenna
• $G$ = Gain of the Antenna
• $\lambda$ = Wavelength = $c/frequency$, where $c = 3 \times 10^8$ m/s
• $p_t$ = Peak transmit Power
• $d$ = Distance between radar and target
• $L_t$ = Transmitter losses
• $L_r$ = Receiver losses
• $L_m$ = Medium losses
• $\sigma_M$ = Radar Cross Section of the target

Bistatic Radar

Overview

Bistatic radar, unlike its monostatic counterpart, employs two separate antennas for transmitting and receiving signals. These antennas are also located at different physical locations.

Block Diagram

Figure 2: Bistatic radar block diagram.

Figure 2 illustrates the setup of a bistatic radar system. A classic example of a system that can be configured as either bistatic or monostatic is CW (Continuous Wave) radar. When the distance between the antennas is minimal, it functions as a monostatic radar.

Bistatic Radar Equation

The equation governing the performance of a bistatic radar system is:

Where:

• $P_R$ = Total power received at the receiving antenna
• $G_t$ = Gain of the transmitting antenna
• $G_r$ = Gain of the receiving antenna
• $\lambda$ = Wavelength = $c/frequency$, where $c = 3 \times 10^8$ m/s
• $p_t$ = Peak transmit Power
• $d_t$ = Distance between object and radar transmitting antenna
• $d_r$ = Distance between object and receiving antenna of radar
• $L_t$ = Transmitter losses
• $L_r$ = Receiver losses
• $L_m$ = Medium losses
• $\sigma_B$ = Radar Cross Section of the target = $\frac{4\pi A_e^2}{\lambda^2}$ (where $A_e$ is object projected area)