- Antenna Array Far Field Radiation Pattern
- Antenna Array with Mutual Couplings
- Similarities of Filter vs. Antenna
- Why Antenna Surrounding Matters?
- Antenna Array Factor over Ground Plane
- WiGig Antenna
- Multi Band Antenna
- Triple Bands VHF and UHF Antennas
Triple Bands VHF and UHF Antennas
VHF and UHF mobile handheld (Walkie Talkie) radios are utilized by many.
Due to operating wavelength, they have range from few to tens of kilometers depending on the environment and condition.
The mobility requires compact, low weight, low power radio. Antenna design Triple Bands topology is highly desired.
Partner with ORTENGA for your mutliband antenna design and development.
Multi Band Antenna
BT and WiFi share 2.4 GHz ISM band. In addition, WiFi technology has 5 and 6 GHz bands.
A router or handheld device which supports both BT and WiFi would need to support multi band between 2 to 7 GHz. Therefore, designing antenna aperture and radio front end that support multi bands is highly desirable.
In the case of wearable devices, the form factor of the mobile device is of prime concern.
In addition, the material and proximity in close space becomes challenging for typical antenna designer.
Augment ORTENGA in your wearable multi band antenna design and development.
WiGig Antenna subsystem would require 25% fractional bandwidth. The antenna subsystem module would be comprised of apertures, feeding and impedance matching networks. The more sophisticated antenna subsystem could even have dynamic impedance and aperture matching network which is are tailored for the used channel on the fly.
Advanced 5G or even 6G wireless systems will support holographic 3D connectivity for virtual reality, which requires 10’s of Gbps connection. The access points will be local and available at designated location where virtual reality services are supported.
This technology will be relying on both beamforming and MIMO.
Augment ORTENGA for WiGig antenna subsystem design and development.
Antenna Array Far Field Radiation Patterns
Antenna arrays are used to achieve higher directivity relative to the array element.
The radiation pattern of an array can be computed as
Far Field Radiation Pattern = |EF * PF * AF|2
where, EF, PF, and AF are Element Factor, Pattern Factor, and Array Factor.
Element Factor is infinitesimal factor of single element antenna
Pattern Factor is radiation pattern of single antenna due to its current distribution over the antenna
Array Factor is radiation pattern of array due to isotropic element
Each of the above factors can be computed standalone and their products is Far Field Radiation Pattern of the array.
For instance, Marconi-Franklin Linear array antennas are stacked 3 dipole antenna. The element factor is Hertzian dipole pattern. The Pattern factor is the radiation pattern of single dipole due to sinusoidal current excitation or distribution. And the Array factor is the pattern due to isotropic elements array.
Antenna Array with Mutual Couplings
When calculating antenna array pattern for complete accuracy, the pattern of an array antenna must include the variations in the excitation currents as well as the pattern of each element acting under the influence of all coupling effects. This is a difficult task if not impossible; however there are 2 techniques for addressing this problem, namely; isolated element and active element pattern approach. In the isolated element pattern approach, the coupling effect is accounted for in the current excitation and is appropriate for very large arrays. In the active element pattern approach, all coupling effects are accounted for through the active element.
Antenna vs. Frequency Selective Filter
From the electrical engineering perspective, a filter is a device that passes signals of interest in the desired frequency band while discriminating other/undesired frequencies.
An antenna is typically considered a transducer device, which converts guided electromagnetic waves to spherical waves.
Both filters and antennas are typically passive devices and reciprocal (i.e. input and output can be swapped). What is less known about antenna, yet can be mathematically shown is that it behaves as a “spatial filter”.
From the Fourier Transform theory, we know that a narrow pulse, in time domain, has a wide frequency/spectral content (i.e. time and frequency are reciprocal to each other). To pass such a narrow pulse signal, a wide band filter is required. Similarly, a narrow far-field antenna radiation pattern requires to pass wide “spatial frequencies”. In other words, the antenna has to be electrically large (i.e. relative to wavelength). That is why, in the radio astronomy community, an antenna is viewed as “spatial filter”.
Antenna performance not only depends on its design topology but also on the surroundings which impacts antenna impedance in real world application.
In other words, if one were to design an antenna and meets all its required performance in standalone condition, then when it is embedded with other radio components, the antenna behavior would change, either over frequency or for worst.
In fact, mobile handset antennas are tuned with human phantom after fabrication, to adjust tuning elements in such a way that meets requirements in presence of the human body.
More advanced mobile handsets have capability of adjusting the tuning elements on the fly to account for various surroundings and still meets acceptable antenna performance.
Very advanced mobile handsets have capability of adjusting impedance and aperture tuning elements on the fly.
Antenna Array Factor over Ground Plane
5G NR, gNB, LEO SATCOM, radar, and WiGig rely on beamforming, therefore Active Electronically Scanned Antenna Array, AESA. Typically AESA has ground plane, consequently image theory must be utilized to arrive at proper radiation pattern of AESA for simulation and therefore in actual applications. This particularly becomes important and critical for implementing Beamforming, Beam steering, and SLL management algorithms.
The appropriate simulations enable the architect, system design, and managements to validate assumptions made for feasibility of design. ORTENGA provides simulation tools to validate your design and goes beyond what appropriate Phase Array Tool Box or SystemVue provide, independently.
Augment ORTENGA into your architect and system design teams to validate design before its implementations.