Q-Band Downconverter

Core Frequency Conversion Terms

Upconversion
The process of translating a lower-frequency signal, such as IF or L-band, to a higher RF or millimeter-wave frequency using a mixer and local oscillator. Upconversion is used in transmit chains for satellite communication, radar, telemetry, and wireless systems.

Downconversion
The process of translating a high-frequency RF or millimeter-wave signal to a lower intermediate frequency for filtering, amplification, digitization, or demodulation. Downconversion is fundamental in receiver architectures.

Up-Downconverter
A frequency conversion device that integrates both upconversion and downconversion functions within a single unit, enabling bidirectional frequency translation between RF and IF stages.

Frequency Converter
A general RF component that performs upconversion, downconversion, or both, enabling frequency translation between IF, RF, and millimeter-wave bands.

Intermediate Frequency (IF)
A standardized frequency used between RF and baseband stages to simplify filtering, amplification, and signal processing. Common IF ranges include 70 MHz, 140 MHz, 950–1450 MHz, 950–2150 MHz, and 4–12 GHz.

RF Frequency
The operating radio frequency after conversion. In Mi-Wave 970 / 980 series products, RF frequencies commonly span X-band through Ku-, Ka-, Q-, and V-band.

Local Oscillator (LO) and Mixing Terms

Local Oscillator (LO)
A stable signal source used in a mixer to enable frequency translation. LO quality directly impacts phase noise, spurious performance, and frequency stability.

External LO Input
An externally supplied LO signal used to lock the converter to a system reference, improving synchronization and frequency accuracy across multiple devices.

LO Leakage
Unwanted LO energy appearing at the RF or IF ports. Low LO leakage reduces spurious emissions and interference.

Image Frequency
An undesired frequency that also converts to the same IF during mixing and must be suppressed through filtering or image-reject architectures.

Image Rejection
The ability of a frequency converter to suppress unwanted image frequencies. High image rejection improves receiver sensitivity and spectral purity.

Gain, Power, and Linearity Specifications

Conversion Gain
The net gain or loss introduced by the frequency conversion process. Conversion gain may be fixed or adjustable depending on design.

Gain Flatness
The variation of conversion gain across the operating bandwidth. Low gain flatness variation ensures uniform signal amplitude.

Digital Attenuation
Digitally controlled attenuation used to adjust output or conversion gain in precise, repeatable steps.

Automatic Gain Control (AGC)
A control function that automatically adjusts gain or attenuation to maintain a consistent output level despite input signal variations.

P1dB (1 dB Compression Point)
The output power level at which gain compresses by 1 dB from linear operation. Indicates the usable linear power range of the converter.

Output Power
The RF power level available at the output of an upconverter or the IF output of a downconverter.

OIP3 (Output Third-Order Intercept Point)
A measure of linearity indicating how well the device handles multiple signals without generating intermodulation distortion.

Noise and Signal Quality Metrics

Noise Figure (NF)
A measure of how much noise a component adds to the signal. Low noise figure is critical in downconverters and receiver front ends.

Phase Noise
Short-term frequency fluctuations of the LO or output signal, typically expressed in dBc/Hz. Low phase noise supports high-order modulation and radar resolution.

Frequency Stability
The ability of a converter or LO to maintain accurate frequency over time, temperature, and environmental conditions.

Reference Input
An external frequency reference, commonly 10 MHz, used to lock the LO and synchronize multiple RF systems.

Bandwidth and Channel Characteristics

Instantaneous Bandwidth
The frequency range over which the converter operates at a single tuning setting without retuning.

Operational Bandwidth
The total frequency span supported by the converter across its tuning range.

Tuning Resolution (Step Size)
The smallest frequency increment by which the LO or output frequency can be adjusted.

Multichannel Operation
A configuration where multiple independent frequency conversion paths operate in parallel within a single unit.

Spurious and Spectral Performance

Spurious Responses (Spurs)
Unwanted discrete frequency components generated by mixing products, harmonics, or nonlinearities.

Signal-Related Spurious
Spurious signals directly related to the input or output signal frequency.

Non-Signal-Related Spurious
Spurious emissions not directly tied to the signal frequency, often caused by internal oscillators or digital circuitry.

Harmonic Suppression
The attenuation of harmonic frequencies generated by nonlinear RF components.

Spectral Purity
The cleanliness of the output spectrum, characterized by low phase noise, low spurious content, and strong image suppression.

Interfaces, Packaging, and Integration

WR-Waveguide Interface
A standardized rectangular waveguide used for millimeter-wave RF interfaces, such as WR-28 (Ka-band) or WR-22 (Q-band).

Coaxial IF Interface
A coaxial connector, such as SMA or N-type, used for IF input or output connections.

Coupled Test Port
A low-level monitoring output that allows signal verification without interrupting the main RF path.

Commercial Rack-Mount Packaging
An enclosure designed for indoor laboratory, test, and ground-station installations.

Ruggedized or Environmental Packaging
Sealed or reinforced enclosures designed for outdoor, airborne, or harsh operating environments.

System-Level Terms

Receiver Front-End Protection
The use of frequency converters and filtering to prevent strong signals from overloading LNAs and mixers.

Dynamic Range
The range between the smallest and largest signal levels that can be processed without excessive noise or distortion.

Synchronization
The alignment of frequency and phase across multiple converters or channels using a common reference.

Regulatory Compliance
Ensuring frequency-converted signals meet emission limits and spectral mask requirements imposed by regulatory authorities.