Propagasi Gelombang Pertemuan 8 Matakuliah: H0122 / Dasar Telekomunikasi Tahun: 2008

Bina Nusantara 2 Mahasiswa dapat menjelaskan berbagai cara sinyal berpropagasi pada atmosfir dan ruang hampa serta fungsi antena. Learning Outcomes

Bina Nusantara 3 Pengertian Propagasi gelombang Polarisasi Jenis Antena Outline Materi

Bina Nusantara 4 Wave Propagation Once a radio signal has been radiated by an antenna, it travels or propagates through space and ultimately reaches the receiving antenna. The energy level of the signal decreases rapidly with distance from the transmitting antenna. The electromagnetic wave is affected by objects that it encounters along the way such as trees, buildings, and other large structures. The path that an electromagnetic signal takes to a receiving antenna depends upon many factors, including the frequency of the signal, atmospheric conditions, and time of day.

Bina Nusantara 5 Characteristics Waves  Radio waves act much like light waves.  Light waves can be reflected, refracted, diffracted, and focused by other objects.  The focusing of waves by antennas to make them more concentrated in a desired direction is comparable to a lens focusing light waves into a narrower beam.

Bina Nusantara 6 Radio Waves Types Radio-Wave Propagation Through Space The three basic paths that a radio signal can take through space are: Ground wave Sky wave Space wave

Bina Nusantara 7 Ground Wave

Bina Nusantara 8 Line of Sight

Bina Nusantara 9 Sky Wave Use the ionospheres layers to reflect the signal back to earth

Bina Nusantara 10 Fungsi antena Meradiasikan energi ke sekeliling (untuk transmisi) atau menangkap energi dari sekeliling (untuk penerimaan) Prinsip Antenna Reciprocity Suatu antena dirancang untuk mengirim dan dapat dipakai untuk menerima Antena

Bina Nusantara 11 Radiation field pattern Gain Lobes Beamwidth Directivity Radiation angle Bandwidth Polarization Antenna Parameters

Bina Nusantara 12 Formed by spreading the conductors of the two-wire transmission line out into a straight line. Impedance is purely resistive at 73 Ω Also called as Hertz Antenna Dipole

Bina Nusantara 13 Bandwidth is about 10% greater than the open dipole The folded dipole impedance is 292 Ω Folded Dipole

Bina Nusantara 14 Array Antenna Log Periodic Antenna Phased Array Antenna Slot Antenna Multiple Element

Bina Nusantara 15 To shape the radiation pattern of the antenna field to focus it more sharply and thus increase the apparent power or gain in a specific direction Three basic elements : the active, powered, or driven element plus the director, and the reflector Yagi-Uda array is a single driven element which has enough capability and flexibility Array

Bina Nusantara 16 Telah dipelajari karakteristik propagasi gelombang. Telah dipelajari berbagai jenis antenna. Summary