user:kurser:ham_vt2023_l7
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| user:kurser:ham_vt2023_l7 [2023/04/07 12:35] – user | user:kurser:ham_vt2023_l7 [2023/04/11 08:44] – user | ||
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| ==Antennas== | ==Antennas== | ||
| - | Show some example antennas. | + | Antenna = two port that converts energy from propagating in a transmission line to propagation in free-space. |
| - | * Ground plane/verticals | + | |
| - | * Loop antennas | + | Characterized by: |
| + | * Input impedance, SWR, Z_in | ||
| + | * Operation frequency, resonance frequency, f_0 | ||
| + | * Directivity D, antenna gain, dBi, dBd | ||
| + | * far field distance = d_f > 2*D^2/lambda, given d_f >> D, d_f >> lambda | ||
| + | * Radiation efficiency, eta | ||
| + | * radiation pattern, E & H patterns | ||
| + | * Polarization and x-pol suppression and so on... | ||
| + | |||
| + | We can only measure input impedance and operational frequency easily with a VNA/Antena analyzer ... so lets do that at ETA. | ||
| + | |||
| + | Different types | ||
| + | * Dipole | ||
| + | * Monopole | ||
| + | * Small loop | ||
| * Yagi | * Yagi | ||
| - | * log periodic | + | * Quad |
| - | * Parabolic | + | * Patch |
| - | * etc. | + | * Bowtie |
| + | * PCB/PIFA | ||
| + | * Spiral/ | ||
| Talk about polarization. | Talk about polarization. | ||
user/kurser/ham_vt2023_l7.txt · Last modified: 2024/02/13 18:08 by user