Search for answers or browse our Knowledge Base.
Guides | Models | Validation | Blog
-
Guides
-
-
- Modeling Common-Mode Currents in Coaxial Cables: A Hybrid Approach
- Evaluating EMF Compliance - Part 2: Using Near-Field Calculations to Determine Exclusion Zones
- Beyond Analytical Formulas: Accurate Coil Inductance Calculation with AN-SOF
- Complete Workflow: Modeling, Feeding, and Tuning a 20m Band Dipole Antenna
- DIY Helix High Gain Directional Antenna: From Simulation to 3D Printing
- Evaluating EMF Compliance - Part 1: A Guide to Far-Field RF Exposure Assessments
- Design Guidelines for Skeleton Slot Antennas: A Simulation-Driven Approach
- Simplified Modeling for Microstrip Antennas on Ungrounded Dielectric Substrates: Accuracy Meets Simplicity
- Fast Modeling of a Monopole Supported by a Broadcast Tower
- Linking Log-Periodic Antenna Elements Using Transmission Lines
- Wave Matching Coefficient: Defining the Practical Near-Far Field Boundary
- AN-SOF Mastery: Adding Elevated Radials Quickly
- Enhancing Antenna Design: Project Merging in AN-SOF
- On the Modeling of Radio Masts
- RF Techniques: Implicit Modeling and Equivalent Circuits for Baluns
- AN-SOF Antenna Simulation Best Practices: Checking and Correcting Model Errors
- Show All Articles (1) Collapse Articles
-
-
- AN-SOF 9.50 Release: Streamlining Polarization, Geometry, and EMF Calculations
- AN-SOF 9: Taking Antenna Design Further with New Feeder and Tuner Calculators
- AN-SOF Antenna Simulation Software - Version 8.90 Release Notes
- AN-SOF 8.70: Enhancing Your Antenna Design Journey
- Introducing AN-SOF 8.50: Enhanced Antenna Design & Simulation Software
- Get Ready for the Next Level of Antenna Design: AN-SOF 8.50 is Coming Soon!
- Explore the Cutting-Edge World of AN-SOF Antenna Simulation Software!
- Upgrade to AN-SOF 8.20 - Unleash Your Potential
- AN-SOF 8: Elevating Antenna Simulation to the Next Level
- New Release: AN-SOF 7.90
- AN-SOF 7.80 is ready!
- New AN-SOF User Guide
- New Release: AN-SOF 7.50
- AN-SOF 7.20 is ready!
- New Release :: AN-SOF 7.10 ::
- AN-SOF 7.0 is Here!
- New Release :: AN-SOF 6.40 ::
- New Release :: AN-SOF 6.20 ::
- Show All Articles (3) Collapse Articles
-
-
-
-
Models
-
- Download Examples
- Modeling a Center-Fed Cylindrical Antenna with AN-SOF
- Yagi-Uda Array
- Monopole Over Real Ground
- Helix Antenna in Axial Mode
- Modeling a Circular Loop Antenna in AN-SOF: A Step-by-Step Guide
- A Transmission Line
- An RLC Circuit
- Explore 5 Antenna Models with Less Than 50 Segments in AN-SOF Trial Version
-
- Modeling a Super J-Pole: A Look Inside a 5-Element Collinear Antenna
- Simulating the Ingenious Multiband Omnidirectional Dipole Antenna Design
- The Loop on Ground (LoG) Antenna: A Compact Solution for Directional Reception
- Precision Simulations with AN-SOF for Magnetic Loop Antennas
- Advantages of AN-SOF for Simulating 433 MHz Spring Helical Antennas for ISM & LoRa Applications
- Radio Mast Above Wire Screen
- Square Loop Antenna
- Receiving Loop Antenna
- Monopole Above Earth Ground
- Top-Loaded Short Monopole
- Half-Wave Dipole
- Folded Dipole
- Dipole Antenna
- The 5-in-1 J-Pole Antenna Solution for Multiband Communications
-
- The Lazy-H Antenna: A 10-Meter Band Design Guide
- Extended Double Zepp (EDZ): A Phased Array Solution for Directional Antenna Applications
- Transmission Line Feeding for Antennas: The Four-Square Array
- Log-Periodic Christmas Tree
- Enhancing VHF Performance: The Dual Reflector Moxon Antenna for 145 MHz
- Building a Compact High-Performance UHF Array with AN-SOF: A 4-Element Biquad Design
- Building a Beam: Modeling a 5-Element 2m Band Quad Array
- Broadside Dipole Array
- Log-Periodic Dipole Array
- Broadband Directional Antenna
- A Closer Look at the HF Skeleton Slot Antenna
- The 17m Band 2-Element Delta Loop Beam: A Compact, High-Gain Antenna for DX Enthusiasts
- Enhancing Satellite Links: The Moxon-Yagi Dual Band VHF/UHF Antenna
-
-
Validation
-
-
- Simple Dual Band Vertical Dipole for the 2m and 70cm Bands
- Linear Antenna Theory: Historical Approximations and Numerical Validation
- Validating Panel RBS Antenna with Dipole Radiators against IEC 62232
- Validating V Antennas: Directivity Analysis with AN-SOF
- Enhanced Methodology for Monopoles Above Radial Wire Ground Screens
- Dipole Gain and Radiation Resistance
- Convergence of the Dipole Input Impedance
- Validating Dipole Antenna Simulations: A Comparative Study with King-Middleton
-
Front-to-Rear and Front-to-Back Ratios: Applying Key Antenna Directivity Metrics
Two commonly used metrics for quantifying the directional properties of an antenna radiation pattern are the front-to-rear ratio (F/R) and the front-to-back ratio (F/B). Both F/R and F/B are crucial parameters for evaluating antenna performance, especially in applications requiring high directivity and low interference, such as point-to-point communication links and satellite systems.
- F/R is the ratio of the maximum power radiated by the antenna in the forward direction to the maximum power radiated in the backward direction. It indicates the antenna’s directional gain in the forward direction relative to its backward radiation. A high F/R signifies strong forward radiation and low backward radiation.
- F/B is the ratio of the maximum power radiated by the antenna in the forward direction to the power radiated in the opposite direction. It measures the power difference between the front and the directly opposing side of the antenna. A high F/B also implies strong forward radiation and low radiation in the opposite direction.
Both F/R and F/B are typically expressed in decibels (dB).
Metric | Definition |
---|---|
F/R (Worst-case Front-to-Back) | Ratio of maximum forward power to maximum backward power |
F/B (180°-Front-to-Back) | Ratio of maximum forward power to power at 180 degrees |
Figure 1 illustrates the difference between F/R and F/B, assuming a 360-degree radiation pattern slice.
In summary, the primary distinction between F/R and F/B lies in the direction of backward radiation. F/R compares the maximum forward power to the maximum backward power, while F/B compares the maximum forward power to the power radiated in the opposite direction.
These definitions are applicable to both horizontal (θ = const.) and vertical (φ = const.) radiation patterns in free space. However, the presence of a ground plane introduces complexities. For horizontal patterns, F/R and F/B calculations remain unchanged as the angular range spans 360 degrees. Conversely, for vertical patterns, the angular range is limited to 180 degrees. In this case, F/R is redefined as the front-to-side ratio, comparing the maximum signal to the maximum signal in the opposite quadrant (as depicted in Fig. 2). F/B becomes irrelevant due to the absence of a ‘back’ direction for an infinite ground plane, resulting in a zero value from AN-SOF.
Understanding F/R and F/B is crucial for effective antenna design. The Results tab in the AN-SOF main window presents F/R and F/B values in dB as a function of frequency for both vertical (V) and horizontal (H) radiation pattern slices. The Plots tab offers a visual comparison of F/R and F/B over the frequency range.
Note:
- To ensure proper calculations of F/R and F/B, select the Full 3D, Vertical or Horizontal options in the Far-Field panel.
Golden Engineering
- Selecting the Custom option in the Far-Field panel will lead to variations in the calculation of F/R and F/B as they will depend on the specific angular ranges that have been configured.