Broadband receiver front-ends spanning the L, S, C, X, Ku, and K microwave bands require a careful balance between operating bandwidth, input sensitivity, and gain flatness. In wideband reception chains, the primary low noise amplifier (LNA) must provide sufficient gain to override conversion losses and noise contributions from downstream mixers, filters, and switches without prematurely compressing under strong signals. The 1–26 GHz Broadband Low Noise Amplifier Module provides 32.5 dB typical small-signal gain and a 3.3 dB typical noise figure across a contiguous 25 GHz bandwidth, housed in a compact 30 × 20 × 10 mm coaxial enclosure. This 1–26 GHz LNA is intended for wideband receiver front ends and test systems where low noise and high gain are prioritized over maximum input linearity. Evaluating this module for system integration requires analyzing its gain-versus-linearity profile against wider-bandwidth alternatives, calculating its cascaded noise figure impact via Friis’ formulation, and managing supply decoupling on its 15V DC rail.
Specification Comparison: 1–26 GHz vs. 0.1–20 GHz Coaxial Modules
Comparing the 1–26 GHz module against an extended-bandwidth alternative highlights the trade-off between higher upper-frequency reach, gain, and output compression:
Technical Specs & Engineering Support
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| Specification Parameter | 1-26GHz LNA (High Gain / Low NF) | 0.1-20GHz LNA (Extended Linearity) | Engineering Trade-Off |
| Frequency Range | 1000 – 26000 MHz (1 – 26 GHz) | 100 – 20000 MHz (0.1 – 20 GHz) | Microwave coverage through K-band vs. decade RF/microwave coverage |
| Small-Signal Gain | 32.5 dB (typical) | 24 dB (typical) | +8.5 dB higher gain to override high-loss downstream stages |
| Noise Figure (NF) | 3.3 dB (typical) | 5.0 dB (typical) | 1.7 dB lower noise figure for maximum weak-signal sensitivity |
| Output P1dB | +10 dBm (typical) | +17 dBm (typical) | +7 dB higher output compression ceiling on 0.1–20 GHz unit |
| Operating Voltage | 15 V | 15 V | Identical 15V DC rail compatibility |
| Dimensions | 30 × 20 × 10 mm | 30 × 25 × 15 mm | Lower-profile package (10 mm vs. 15 mm height) |
Downstream Noise Suppression & Friis Formulation
In multi-octave microwave systems, wideband passive components downstream of the LNA—such as double-balanced mixers, switch matrices, and preselection equalizers—often exhibit conversion losses or noise figures between 8 dB and 12 dB.
According to Friis’ formula for total noise factor:
F_total = F1 + (F2 – 1) / G1 + (F3 – 1) / (G1 * G2)
Where:
- F1 is the noise factor of the first-stage LNA (a 3.3 dB typical NF corresponds to F1 ≈ 2.14).
- G1 is the linear power gain of the LNA (a 32.5 dB typical gain corresponds to G1 ≈ 1778).
- F2 is the noise factor of the second-stage component (for example, a mixer with a 10 dB noise figure has F2 = 10).
Because the linear gain G1 is 1778, the second-stage noise contribution (F2 – 1) / G1 evaluates to (10 – 1) / 1778 ≈ 0.0051. Adding this to F1 yields:
F_total ≈ 2.14 + 0.0051 = 2.1451 (equivalent to ~3.31 dB total NF)
Because of this high front-end gain, the noise contribution of subsequent stages is largely suppressed, allowing the front-end sensitivity to remain dictated almost entirely by the LNA’s 3.3 dB noise figure. With only 15–20 dB of first-stage gain, downstream mixer and filter noise can make a more measurable contribution to the overall receiver noise figure, depending on the gain and noise figure of subsequent stages.
Linearity and Input Power Handling
While 32.5 dB of gain optimizes sensitivity for weak signals, it establishes a lower input compression ceiling relative to lower-gain stages:
- Input 1dB Compression Estimate: A first-order estimate of the input-referred P1dB is approximately -22.5 dBm, calculated from the specified +10 dBm typical output P1dB and 32.5 dB typical small-signal gain:Input P1dB ≈ Output P1dB – Gain = +10 dBm – 32.5 dB = -22.5 dBmActual input compression should be confirmed from measured gain-compression curves.
- Operating Considerations: In environments characterized by strong out-of-band blockers or nearby high-power emitters, an external limiter or tracking preselector may be required ahead of the LNA to protect against intermodulation and front-end saturation.
- Alternative Configuration: When higher input linearity is needed and a 5.0 dB noise figure is acceptable, the 0.1-20GHz LNA provides an output P1dB of +17 dBm with 24 dB of gain (yielding an estimated input P1dB of approximately -7 dBm), offering greater input dynamic range before saturation.
Packaging, DC Supply, and Multi-Stage Stability
Housing a 32.5 dB multi-stage microwave amplifier inside a 30 × 20 × 10 mm coaxial enclosure requires disciplined mechanical and electrical implementation:
- RF Isolation: Delivering over 32 dB of gain across 1 to 26 GHz in a compact 30 mm enclosure requires adequate RF isolation between the input and output paths to prevent feedback-induced instability and maintain flat gain response across the entire band.
- 15V DC Bias Management: The 15 V supply should be well regulated and properly decoupled with low-ESR bypass capacitors near the module DC feed to minimize supply-related noise and maintain phase stability.
- Thermal and Mechanical Mounting: For integrated installations, a low-impedance thermal and mechanical mounting path can help manage the module’s operating temperature, ensuring repeatable electrical performance over extended operational periods.
Engineering Selection & Integration Notes
Q: Why choose the 1–26 GHz LNA over the 0.1–20 GHz LNA?
A: The 1–26 GHz LNA is preferred when system coverage extends into the K-band (20–26 GHz) and weak-signal sensitivity is the primary requirement. Its 3.3 dB typical noise figure and 32.5 dB typical gain maximize front-end sensitivity for wideband receiver front ends, spectrum monitoring, satellite test systems, and RF measurement equipment. The 0.1–20 GHz LNA is chosen when coverage down to 100 MHz is required, or when higher input power handling (+17 dBm output P1dB) is needed to operate in high-signal environments.
Q: How does 32.5 dB of gain affect digitizer or ADC interfacing?
A: With 32.5 dB of gain, the LNA can significantly increase the signal level presented to a downstream ADC. The digitizer’s allowable input range, anti-alias filtering, and any required attenuation should therefore be considered during system-level gain planning to avoid overdriving the converter front end.
Q: What factory calibration data is typically provided for prototype verification?
A: Standard module evaluation includes 100% noise parameter calibration across the operating band, with individual serial-numbered test reports and measured noise figure curves supplied to support bench verification and cascaded link modeling.