Wireless Spectrum Visualizer
From cellular low-bands to terahertz — explore how each generation uses the electromagnetic spectrum.
Updated April 2026Low-band
4G/5G600 MHz – 1 GHz
Wide coverage, building penetration. Used for rural and indoor 4G/5G. Limited capacity.
Mid-band
4G/5G1 – 3 GHz
Sweet spot for 5G: good balance of coverage and capacity. C-band (3.5 GHz) is the workhorse of 5G.
C-band / Sub-6
5G3.5 – 6 GHz
Primary 5G deployment band globally. 100–200 MHz channel bandwidth. Most 5G users are on this band.
Upper mid-band
5G-A/6G6 – 7.125 GHz
New spectrum for 5G Advanced and early 6G. WiFi 6E/7 also operates here. IMT identification ongoing.
mmWave low
5G24 – 40 GHz
5G mmWave: ultra-high capacity for dense urban areas and venues. Short range, requires line-of-sight.
mmWave high
5G/6G40 – 100 GHz
Upper mmWave bands. W-band (75–110 GHz) explored for 6G backhaul and fixed wireless access.
Sub-THz
6G100 – 300 GHz
6G candidate bands. Massive bandwidth (10+ GHz channels), but high atmospheric absorption and short range. Key 6G research area.
Terahertz
7G300 GHz – 3 THz
7G vision bands. Potentially 100+ Tbps, but extreme propagation challenges. Nano-scale antennas, in-body networks, holographic communication.
Far-THz / Infrared
7G+3 – 10 THz
Theoretical far-future bands. Overlap with infrared. Primarily for ultra-short-range chip-to-chip and nano-networks.
The Bandwidth Explosion
Each generation moves higher in frequency to access more bandwidth. A single 6G sub-THz channel could be 10 GHz wide — that's more than all current 5G spectrum combined. The tradeoff: higher frequency means shorter range, more atmospheric absorption, and the need for new antenna technologies.
Spectrum Allocation: How It Works
Radio spectrum is a finite natural resource often called "digital real estate." Governments and international bodies manage its allocation to prevent interference and ensure fair access. The International Telecommunication Union (ITU) coordinates global spectrum use through World Radiocommunication Conferences (WRC), held every 3–4 years, where nearly 200 nations negotiate which frequency bands can be used for which services — including mobile broadband, satellite, radar, and scientific research.
Spectrum licensing follows two primary models: exclusive licensing, where a single operator wins rights to a band (typically through auction), and shared access, where multiple users operate under coordination rules. The United States raised over $233 billion in spectrum auctions since 1994 (FCC data). In shared models like CBRS (3.5 GHz band in the US), tiered priority allows incumbents, priority licensees, and general access users to coexist — a model gaining traction as available exclusive-use spectrum becomes scarce.
For 6G and 7G, the spectrum allocation challenge intensifies. The sub-THz and terahertz bands (100 GHz – 3 THz) have never been licensed for mobile services. WRC decisions in 2023 and upcoming conferences will determine how these bands are shared between mobile, fixed, passive sensing, and scientific services. The outcome will shape whether 7G can achieve its theoretical multi-terabit capacity or remain bandwidth-constrained.
The Physics of Higher Frequencies
The fundamental tradeoff in wireless communications is that higher frequencies provide more bandwidth but suffer greater propagation losses. Free-space path loss increases with the square of frequency — a 300 GHz signal experiences 40 dB more loss than a 3 GHz signal at the same distance. Add atmospheric absorption and things worsen: oxygen molecules resonate near 60 GHz, creating an absorption peak of ~15 dB/km, while water vapor absorbs strongly at 183 GHz and 325 GHz. These "absorption windows" dictate which sub-THz bands are viable for terrestrial communication.
Rain fade is another critical factor. At 100 GHz, moderate rain (25 mm/hr) causes attenuation of approximately 10 dB/km. At 300 GHz, the same rain produces over 30 dB/km loss, effectively limiting outdoor cell radius to tens of meters during storms. Building penetration is equally challenging: a standard exterior wall attenuates a 100 GHz signal by 30–50 dB, compared to 5–10 dB at sub-6 GHz frequencies. This means terahertz 7G will require indoor base stations or repeaters for reliable coverage.
Despite these challenges, the available bandwidth is enormous. Below 6 GHz, the entire allocated mobile spectrum across all operators is roughly 1–2 GHz. A single channel at 300 GHz could span 20–50 GHz — enabling peak data rates beyond 1 Tbps with advanced modulation. Engineers are developing solutions including ultra-massive MIMO arrays (1000+ elements), reconfigurable intelligent surfaces (RIS), and molecular absorption-aware routing to overcome propagation barriers while harvesting this bandwidth.
Key Spectrum Decisions Ahead
The World Radiocommunication Conference 2027 (WRC-27) will be pivotal for next-generation wireless. A primary agenda item is the identification of spectrum between 7 and 24 GHz for IMT (International Mobile Telecommunications) — the so-called "upper mid-band" or FR3. This range offers a compromise between coverage and capacity, and is widely considered essential for early 6G deployments expected around 2030. Bands under study include 7.125–8.4 GHz and 14.8–15.35 GHz.
Beyond WRC-27, sub-THz allocation (92–300 GHz) for mobile use will likely dominate WRC-31 discussions. Current ITU Radio Regulations allocate these bands primarily to fixed, satellite, and passive services like radio astronomy and Earth exploration. The 275–296 GHz band, for example, contains spectral lines critical for atmospheric science. Any mobile allocation must include protection criteria to prevent harmful interference to these passive sensors — a complex coexistence challenge that requires both regulatory frameworks and technical mitigation like geographic exclusion zones.
The 7–24 GHz debate also involves incumbent services: fixed satellite (Ku-band, 12–18 GHz), aeronautical radar, and radio navigation. Sharing studies are ongoing at ITU-R Working Parties 5D and 5A to determine compatible power levels and deployment densities. The decisions made in the next 3–5 years will define whether 6G has sufficient spectrum for its promised 100x capacity improvement over 5G, and whether 7G research can proceed with regulatory certainty in the THz domain.