LABORATORY 17 · ELECTRONICS & COMMUNICATION

Pyramidal Horn Antenna Directivity and Absolute Gain via Three-Antenna Method

Determine the absolute gain and aperture efficiency of an X-band (10 GHz) pyramidal horn antenna using the Friis transmission formula and the standardized three-antenna substitution technique. Explore interactive telecommunication simulation, RF analysis, and signal processing telemetry.

ANALOG MODULATION · DIGITAL BASEBAND · PASSBAND MODULATION · ANTENNAS & RF · OPTICAL FIBER · DSP

Your virtual electronics & communication engineering laboratory.

LINEAR RECEIVED RF POWER LEVEL P_REC—

RF INSTRUMENTATION TELEMETRY

Ready to sample with Inverse Distance Squared = 0.4 m⁻².

Inverse Squared Distance (1/d²)0.4 m⁻²Set Inverse Distance Squared (m⁻²)

Excitation locked to low-phase-noise synthesized reference oscillator.

Adjust Inverse Distance Squared, then execute telecommunication RF/baseband acquisition.

Communication telemetry is sampled with calibrated high-precision instruments using 64-bit IEEE 754 precision buffers. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity modulation, channel, and spectral analysis.

Communication engineering assumptions and boundary limits

Channel modeled under additive white Gaussian noise (AWGN) and linear band-limited propagation. Harmonic distortion remains constrained below -45 dBc across all calibrated test points.

Laboratory apparatus & testing equipment.

Horn Antenna Directivity Telecommunication Workstation

Provides regulated RF/baseband excitation, precision impedance-matched test fixtures, and low-noise interconnection for aperture illumination efficiency, e-plane/h-plane flaring & raylegh far-field distance.

6.5-Digit True-RMS Digital Multimeter (Keysight / Fluke)

Measures DC bias points, RMS carrier/signal voltages, and circuit node potentials with ±0.0035% baseline accuracy.

Four-Channel Digital Storage Oscilloscope (200 MHz, 2 GSa/s)

Captures high-frequency RF envelopes, baseband eye diagrams, constellation patterns, and transient responses for horn antenna directivity.

Synthesized Vector RF Signal Generator (9 kHz – 3 GHz)

Delivers calibrated, low-phase-noise continuous-wave and modulated carrier signals to establish inverse distance squared conditions.

High-Dynamic-Range RF Spectrum Analyzer (9 kHz – 3.6 GHz)

Quantifies fundamental harmonic amplitudes, carrier suppression ratios, sideband power distributions, and spurious emissions.

Matched 50-Ohm Coaxial Interconnects & Attenuator Set

Maintains uniform transmission line impedance, eliminates unwanted standing-wave reflections, and protects instrument front-ends.

FOLLOW THE METHOD

A reason behind every step.

Determine the absolute gain and aperture efficiency of an X-band (10 GHz) pyramidal horn antenna using the Friis transmission formula and the standardized three-antenna substitution technique. Standardized parameter settings: 0.0625, 0.1111, 0.25, 0.4444, 0.6944, 1.0 m⁻².

Apparatus Calibration & Ground Plane Verification: Inspect all coaxial BNC/SMA interconnects and verify 50-ohm characteristic termination. Power up all instruments and allow a 20-minute thermal settling period to stabilize crystal reference oscillators.
Carrier & Modulating Signal Synthesis: Configure the synthesized RF signal generator and baseband source to the specified baseline parameters. Calibrate the inverse distance squared using the precision digital multimeter and oscilloscope.
Systematic Telemetry Acquisition & Setpoint Stepping: Increment the inverse distance squared systematically across the experimental range (0.0625 to 1.0 m⁻²), logging the resulting linear received rf power level p_rec after signal settling.
Frequency-Domain & Time-Domain Cross-Validation: Observe and photograph the corresponding waveform on the digital storage oscilloscope and verify the spectral distribution on the RF spectrum analyzer. Verify that harmonic distortion remains below -45 dBc.
Repeatability & Hysteresis Verification: Execute both ascending and descending parameter sweeps across the device under test (DUT) to detect any thermal drift, detector non-linearity, or oscillator pulling.
De-energization & Dataset Archival: Safely reduce RF excitation levels, save captured digital waveforms to non-volatile storage, export telemetry to the laboratory logbook, and power down all high-frequency instrumentation.

YOUR NOTEBOOK · 0 OBSERVATIONS

Turn measurements into telecommunication engineering insight.

See a complete example report ↗

Points are your recorded observations. The solid regression line validates Horn Antenna Directivity mathematical scaling.

LINEAR REGRESSION FIT · y = mx + b

P_rec = 45.0000 · (1/d²)

#	Inverse Squared Distance (1/d²) (m⁻²)	Linear Received RF Power Level P_rec (μW)	Inverse squared distance 1/d² (m⁻²)	Received RF power P_rec (μW)

No readings yet. Execute a communication trial and record it.

CHECK YOUR UNDERSTANDING

Explain what the communication metrics mean.

Question 1: In the experimental investigation of Horn Antenna Directivity, the primary dependent variable measured is:

Question 2: The mathematical relationship governing Horn Antenna Directivity is modeled as:

Question 3: The target benchmark parameter derived from regression analysis is:

Question 4: Which instrument provides the most accurate visualization of spectral harmonics and carrier sidebands in the frequency domain?

THEORY AND ELECTROMAGNETIC CONTEXT

Electronics & Communication Engineering background & physical principles.

Determine the absolute gain and aperture efficiency of an X-band (10 GHz) pyramidal horn antenna using the Friis transmission formula and the standardized three-antenna substitution technique.

P_rec = 45.0000 · (1/d²)

Communication systems rely on Fourier spectral decomposition, Shannon channel capacity, and electromagnetic propagation theory.