HF Meander-Line Antenna Simulations and Investigations for NVIS on a HMMV
Technical Report,01 Oct 2015,28 Sep 2016
SPAWAR north chaleston United States
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High Frequency communications aboard navy and marine corps vessels and vehicles continues to be used Navy and DoD wide. Near Vertical Incident Skywaves NVIS are a reliable means to communicate between 30-400 miles and often is used to communicate Beyond-Line-of-sight BLOS when in adverse terrain conditions. Currently fielded monopolewhip antennas are an operational OPSEC hazard and can impact battle communication reliability. Meander-line antennas MLA have been in use for many applications, ranging from Radio Frequency Identification RFID to WLAN communication systems. Typical planar MLA are designed to electrically lengthen the antenna and thereby allowing a lower frequency of operation then a traditional monopole or dipole antenna design. A free space MLA antenna was designed at 7.5 MHz along with an in-situ MLA incorporated into the roof of a HMMV. A 16ft titled whip antenna was also simulated as a comparison metric. Simulations of gain radiation patterns and Z-parameters were collected and documented for all designs and were compared at varying NVIS frequencies. The in-situ MLA would function better as a NVIS radiator between -15 and 15 Phi degrees typical spherical coordinate reference then the simulated tilted whip. However, at other NVIS phi degrees the simulated tilted whip performed better then the incorporated MLA. Even with the in-situ design, there continues to be a large amount of coupling occurring between the radiating elements of an antenna with the vehicle body frame.