To increase a radio system's usable frequency range you combine hardware and software techniques: select or design wideband RF daughterboards, add external up/down-converters or frequency multipliers, deploy wideband low-noise amplifiers (LNAs) and tunable filters, use direct RF sampling ADCs/DACs where possible, implement digital compensation and calibration in the FPGA/host, and integrate switchable front-ends (multi-band daughterboards) or mmWave radio heads to cover bands beyond the native transceiver. These approaches — used alone or together — let research labs, universities and integrators extend sub-6 GHz coverage up to mmWave while preserving sensitivity, linearity and test reproducibility.
Considering a frequency expansion for a 5G, satellite, radar or aerospace testbed? Contact Highmesh for custom daughterboard options, converter modules and integration support.
Practical methods to raise the RF coverage of a USRP/SDR system include:
Install wideband daughterboards that natively tune to broader ranges (e.g., multi-octave designs).
Use external upconverters/downconverters (mixer + LO) to translate sub-6 GHz transceiver bands into mmWave bands and vice versa.
Add frequency multipliers or harmonic mixers for bands where direct sampling is infeasible.
Deploy tunable RF front-ends (switchable filters, tunable LNAs) to maintain performance across wide bands.
Combine multiple daughterboards or radioheads with an RF switching matrix to switch between bands quickly.
Leverage direct RF sampling ADCs/DACs and FPGA DDC/DUC to increase usable instantaneous bandwidth without additional RF stages where sample rates permit.
Common engineering patterns and module types:
Heterodyne conversion chains — low-IF or zero-IF mixers with high quality LOs (fractional-N PLLs) to translate frequencies into the transceiver's native band.
Image-rejection & IQ calibration — DSP routines and analog preconditioning to remove image tones introduced by conversion.
Wideband LNA + distributed amplification — use distributed amplifier topologies for flat gain over multi-octave ranges.
Active or MEMS tunable filters — dynamically change center frequency and bandwidth to reduce out-of-band noise and spurs.
Frequency multiplication chains — use multipliers for mmWave (x2/x3) when direct LO synthesis is limited.
Fewer specialized instruments: one reconfigurable RF stack replaces multiple narrowband testers.
Future-proofing: support new bands (sub-6 GHz → mmWave) without full hardware redesign.
Comprehensive spectrum monitoring: monitor and analyze more bands for interference hunting and coexistence studies.
Reduced integration complexity: fewer platform variants when daughterboards or converter modules are modular.
Cost & space efficiency: scalable approach for lab testbeds and field deployments when compared to many single-band instruments.
Key selection criteria for procurement teams:
Native tuning range and whether the board is single- or multi-octave.
Instantaneous bandwidth vs total tunable span — do you need wide single-shot capture or many narrow slices?
Noise figure, linearity (IP3) and gain flatness across the band.
Connector types and power handling (SMA vs 2.92mm for mmWave).
Compatibility with your USRP/host (mechanical slot, FPGA resources, driver support). See Highmesh RF daughterboards: RF Daughterboards catalog.
To build or choose a wideband amplifier:
Prefer distributed amplifier or wideband feedback topologies for flat gain across octaves.
Choose device technology — SiGe or III-V (GaAs, GaN, HEMT) for high-frequency performance and linearity in mmWave.
Design matched broadband input/output networks (multi-section transformers or resistive matching) to control VSWR.
Include automatic gain control (AGC) and robust thermal management to protect ADCs/DACs from saturation.
Characterize gain flatness, noise figure, and IP3 over temperature; apply digital pre-/post-compensation to correct residual errors.
Advances that enable wider ranges:
Higher-speed ADCs/DACs enabling direct sampling at higher RF or with more flexible DDC/DUC ratios.
Better semiconductor processes (SiGe, GaN) for amplifiers and mixers, giving lower noise and higher fmax.
Improved LO synthesis (fractional-N PLLs, integrated DDS) enabling stable, agile LOs across wide spans.
Better PCB materials and RF layout techniques reducing parasitics and losses at mmWave.
Advanced on-board calibration and digital correction (IQ imbalance, DC offsets, frequency response equalization) performed in FPGA or GPU.
Examples of modern tech that extend coverage:
Direct RF sampling ADCs that remove analog downconversion stages for some bands.
Integrated multi-chip modules combining PLL, mixers, and LNAs into a single RFIC for tunable wideband operation.
Software-tunable RF filters (MEMS/ferroelectric) for dynamic band selection.
Reconfigurable antenna arrays and radioheads for mmWave beamforming and phased array testing.
Digital predistortion and ML-based calibration running on FPGA/CPU to correct nonlinearity across the band.
Practical limits to consider:
ADC/DAC sampling and Nyquist constraints: sampling rate sets an upper bound for direct sampling without aliasing or complex conversion chains.
Component parasitics & PCB losses: traces, substrate dielectric, and vias worsen at mmWave.
LO phase noise and spurs: degrade sensitivity and channel estimation at higher frequencies.
Front-end linearity: intermodulation products and compression limit usable dynamic range.
Connector and coax losses: SMA vs precision mmWave connectors impact insertion loss.
Thermal and mechanical stability: temperature drift and connector repeatability affect calibration and repeatability at high frequencies.
Tuning approaches used in lab and field:
LO switching & fractional-N PLLs to retune mixers fast with low phase noise.
Software control of digital down/up converters (DDC/DUC) to change center frequency and decimation ratios.
RF switch matrices for selecting different front-end chains or antenna feeds.
Automated calibration scripts to remeasure and reapply correction tables after tuning.
Use of multi-band daughterboards that programmatically select RF chains for different bands.
For 5G testbeds you typically need both sub-6 GHz and mmWave coverage:
Use wideband sub-6 GHz daughterboards for initial NR FR1 experiments (MIMO, carrier aggregation).
Combine with external mmWave radioheads or up/down converter modules for FR2 (mmWave) coverage; these modules translate between mmWave and a USRP’s native IF.
Ensure the chosen daughterboard or converter supports the instantaneous bandwidth required by 5G NR carriers (100+ MHz per carrier in some deployments) and supports synchronization (10 MHz / PPS / GPSDO) for multi-node MIMO and beamforming trials. Highmesh offers a range of RF daughterboards and converter options — see Highmesh RF Daughterboards and contact us for recommended 5G combos for the HM X310 or UN210.
Cost varies widely depending on performance and ruggedization:
Entry/modest wideband daughterboards — cost-effective for lab prototyping and education.
High-performance wideband modules & mmWave radioheads — higher unit cost due to precision mixers, LO synthesis, and mmWave packaging.
Converter + radiohead systems add integration and calibration effort (additional cost).
Support, calibration, and warranty for defense/aerospace projects also add to TCO (certifications, environmental testing).
Because exact prices depend on configuration, quantities and support levels, procurement teams should request quotes. Contact Highmesh for pricing and tailored configurations.
When designing or selecting boards consider:
Material selection: low-loss substrates (e.g., Rogers) for mmWave versus FR-4 for lower bands.
Connector & mechanical design: precision RF connectors, controlled impedance transitions and torque specs.
Thermal management: heat pumps, heat spreaders and airflow for continuous high-bandwidth operation.
EMI/EMC and shielding: compartmentalize analog/RF sections to avoid digital noise coupling.
Calibration & factory characterization: produce calibration lookup tables (S-parameters, gain/phase vs freq) and provide easy firmware update paths.
FPGA resources & host interface: ensure the transceiver’s host interface (USB3/PCIe/10GbE) can sustain required data rates and that FPGA has headroom for DDC/DUC kernels and digital correction.
Validate extended frequency designs using:
Vector Network Analyzer (VNA) for S-parameters and matching across bands.
Spectrum analyzer & signal generator for sensitivity, spurious, ACLR and phase noise tests.
Anechoic chamber or shielded enclosures for OTA tests and repeatability.
Automated test scripts to sweep frequency, measure gain/phase, and capture IQ traces for offline analysis.
For research institutes and integration contractors the recommended approach:
Define target bands, instantaneous bandwidth and dynamic range requirements.
Decide whether to extend range via native daughterboards or converters (trade speed vs complexity).
Request demo units and calibrated test scripts from vendor — validate in your lab with VNA and spectrum analyzer.
Plan mechanical, thermal and cable management for field or testbed deployment.
Include firmware/FPGA update and long-term support in procurement contracts.
Highmesh supports full integration: from selecting the right RF Daughterboards to supplying conversion modules and performing on-site validation for HM X310 or UN210 based testbeds. Request a system design consultation.
Specify target bands and instantaneous BW.
Assess ADC/DAC sample-rate headroom and host throughput.
Decide between direct sampling, heterodyne conversion or hybrid approach.
Plan calibration procedures, connectors and mechanical interfaces.
Budget for RF accessories: filters, LNAs, attenuators, mmWave cables and antennas.
Request preproduction samples and validated test scripts from your vendor.
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