One way of outlining the subject of radio science is listing the topics associated with it by authoritative bodies.
The International Union of Radio Science has several commissions corresponding to the following topics of interest:
Commission A - Electromagnetic MetrologyAntennasAtomic-based mechatronicsBioeffects and medical applicationsEMC and EM metrologyHigh-frequency and millimeter wireless metrologyImpulse radarInterconnect and packagingMaterialsMeasurements and calibration in propagationMicrowave to submillimeter measurements/standardsNoiseQuantum metrology and fundamental conceptsSpace plasma characterizationTechniques for remote sensingTest facilitiesTHz metrologyTime and frequencyTime-domain metrologyCommission B - Fields and WavesAntenna arraysAntennas: recent advances and future outlookAntenna theorydesign and measurementsCognitive radioComplex mediabandgap structuresbiologicalgeophysical mediametamaterialsand othersEducational methods and toolsElectromagnetic interaction and couplingGuided waves and waveguiding structuresHigh-frequency techniquesImaginginverse scattering and remote sensingMathematical modeling of electromagnetic problemsMicrostrip antennas and printed devicesMultiphysics electromagneticsNanoscale electromagneticsNonlinear electromagneticsNumerical methodsdifferential-and integral-equation basedhybrid and other techniquesOptical phenomenaOptimization techniques in electromagneticsPropagation phenomena and effectsRough surfaces and random mediaScattering and diffractionTheoretical electromagneticsTHz antennas and propagationTransient fields effects and systemsUltra-wideband electromagneticsWireless communicationsCommission C - Radiocommunication Systems and Signal ProcessingCognitive radio and software-defined radioDistributed sensor networks and sensors array processingEnergy-efficient ("green") communicationsInformation theory, coding, modulation and detectionMIMO and MISO systemsNovel radio communication systemsPhysics-based signal processingRadar target detection, localization, and trackingRadio localization and positioningSignal and image processingSpectrum and medium utilizationStatistical signal processing of waves in random mediaSynthetic aperture and space-time processingWireless networkingCommission D - Electronics and PhotonicsBroadband ubiquitous networkEnergy harvesting in wireless systemsFiber lasers and solid state lasersGraphene nanoelectronics applicationsMulti-physics modeling in radio frequency nanoelectronicsOptical sensors and biosensorsPlasmonicsRF MEMS and NEMSSignal processing antennas60 GHz electronicsTrends in RFID for identification and sensingTrends in THz communicationsCommission E - Electromagnetic Environment and InterferenceCommunication in the presence of noiseCrosstalkElectromagnetic compatibility educationElectromagnetic compatibility measurements and standardsElectromagnetic noise of natural originElectromagnetic radiation hazardsHigh-power effects of transients on electronic systemsSpectrum management and utilizationCommission F - Wave Propagation and Remote SensingPropagation measurements/models for fixed and mobile linksMeasurements of fixed and mobile channelsPropagation modelsMultipath mitigationFixed terrestrial links: measurements and design strategiesSurface/atmosphere interactionDispersion/delayEffects of natural/man-made structuresOutdoor to indoor propagationMulti link MIMO channelsUWB channel characteristics,Small cell propagationRemote sensing of the Earth/planets by radio wavesPassive sensing at millimeter wavelengthsInterferometry and SARSensing of snow in open and forested environmentsRemote sensing of precipitationAtmospheric sensingSensing of soil moisture and biomassOcean and ice sensingUrban environmentsRadio Frequency Interference (RFI)Underground imagingPropagation and remote sensing in complex and random mediaCommission G - Ionospheric Radio and PropagationIonospheric imagingIonospheric morphologyIonospheric modeling and data assimilationRadar and radio techniques for ionospheric diagnosticsSpace weather - radio effectsTransionospheric radio propagation and systems effectsCommission H - Waves in PlasmaChaos and turbulence in plasmaPlasma instabilities and wave propagationSpacecraft-plasma interactionsSolar/planetary plasma interactionsWave-wave and wave-particle interactionsWaves in laboratory plasmasCommission J - Radio AstronomyDetection of short-duration transientsDevelopments in array technology for radio astronomyNew telescopes, techniques, and observationsRadio frequency interference mitigation and spectrum usageSquare Kilometre ArrayTimely technical tutorialsCommission K - Electromagnetics in Biology and MedicineBiological effectsDosimetry and exposure assessmentElectromagnetic imaging and sensing applicationsHuman body interactions with antennas and other electromagnetic devicesTherapeutic, rehabilitative, and other biomedical applicationsThe International Telecommunication Union (ITU) Radiocommunication Sector (ITU-R) has several study groups, each made of working parties, as follows:
Study Group 1 - Spectrum management1A: Spectrum engineering techniques1B: Spectrum management methodologies and economic strategies1C: Spectrum monitoringStudy Group 3 - Radiowave propagation3J: Propagation fundamentals3K: Point-to-area propagation3L: Ionospheric propagation and radio noise3M: Point-to-point and Earth-space propagationStudy Group 4 - Satellite services4A: Efficient orbit/spectrum utilization for the fixed-satellite service (FSS) and broadcasting-satellite service (BSS)4B: Systems, air interfaces, performance and availability objectives for the fixed-satellite service (FSS), broadcasting-satellite service (BSS) and mobile-satellite service (MSS), including IP-based applications and satellite news gathering (SNG)4C: Efficient orbit/spectrum utilization for the mobile-satellite service (MSS) and the radiodetermination-satellite service (RDSS)Study Group 5 - Terrestrial services5A: Land mobile service above 30 MHz (excluding IMT); wireless access in the fixed service; amateur and amateur-satellite services5B: Maritime mobile service including the Global Maritime Distress and Safety System (GMDSS); the aeronautical mobile service and the radiodetermination service5C: Fixed wireless systems; HF and other systems below 30 MHz in the fixed and land mobile services5D: IMT systems (International Mobile Telecommunications)Study Group 6 - Broadcasting service6A: Terrestrial broadcasting delivery6B: Broadcast service assembly and access6C: Programme production and quality assessmentStudy Group 7 - Science services7A: Time signals and frequency standard emissions: Systems and applications (terrestrial and satellite) for dissemination of standard time and frequency signals7B: Space radiocommunication applications: Systems for transmission/reception of telecommanded and tele-metry data7C: Remote sensing systems: for space operation and for space research7D: Radio astronomy: remote sensing systems and applications for Earth exploration meteorology and plantetary sensing.