Dual-circularly-polarized balanced-fed dielectric rod antenna for 60-GHz point-to-point wireless communication

The design of a dual-circularly-polarized balanced-fed dielectric rod antenna for 60-GHz point-to-point communication is described and realized. The measured gain and axial ratio are 15dBi and below 0.5dB, respectively

USAHATANI LADA (PIPER NIGRUM LINN)DI DESA SAHAN KECAMATAN SELUAS KABUPATEN BENGKAYANG KALIMANTAN BARAT

Penelitian ini bertujuan untuk: (1) Mengetahui kesesuaian kondisi fisik dengan syarat tumbuh tanaman lada di Desa Sahan, (2) Mengetahui peranan kondisi non fisik dalam usahatani lada, (3) Mengetahui pengelolaan usaha tani lada di Desa Sahan, (4) Menganalisis hambatan-hambatan apa saja dalam pengelolaan usahatani lada di Desa Sahan, serta upaya apa yang dilakukan untuk mengatasi hambatan tersebut, (5) Mengetahui produktivitas usahatani lada di Desa Sahan. Penelit ian ini merupakan penelit ian deskriptif. Variabel dalam penelit ian ini yaitu syarat tumbuh tanaman lada di Desa Sahan, faktor pengelolaan usahatani lada di Desa Sahan, hambatan yang dihadapi usahatani lada dan produktivitas. Populasi dalam penelit ian ini berjumlah 315 rumah tangga petani lada dan pengambilan sampel 25% yaitu sampel 80 kepala rumah tangga usahatani lada, teknik sampling yang digunakan yaitu proportionate simple random atau sampel campuran. Teknik pengumpulan data dilakukan dengan metode observasi, wawancara, dan dokumentasi. Teknik pengolahan data edit ing, kodit ing, dan tabulasi. Teknik analisis data yang digunakan dalam penelit ian ini adalah analisis deskriptif yaitu proses penyederhanaan data secara deskriptif dengan data frekuensi (tabel tunggal). Hasil penelit ian menunjukkan bahwa: (1) Kesesuaian kondisi fisik yang mempengaruhi usahatani lada memiliki t ingkat kesesuaian yang baik yaitu faktor iklim, sedangkan untuk faktor fisik seperti tanah di daerah penelit ian misalnya seperti pH tanah yang kurang sesuai untuk syarat tumbuh tanaman lada, karena bersifat asam, (2) Peranan kondisi non fisik yang mempengaruhi usahatani lada berkaitan dengan modal, tenaga kerja, pemasaran, transportasi, dan teknologi, (3) Pengelolaan usahatani lada di Desa Sahan adalah pengelolaan lada putih dan lada hitam sebesar 63,75 % dari 80 total keseluruhan responden, (4) Hambatan yang paling besar dihadapi petani lada di Desa Sahan adalah hambatan hama penyakit. Upaya yang dilakukan petani lada di Desa Sahan untuk mengatasi hambatan-hambatan seperti hama penyakit selain dengan cara manual dan pest isida, (5) produktivitas usahatani lada di Desa Sahan dalam satu kali panen per tahun dengan luas lahan 1 ha atau 10.000 m 2 adalah sebesar 2002 kg. Kata kunci : Usahatani Lad

Short-term frequency scaling of clear-sky and wet amplitude scintillation

For the design of uplink power control (ULPC) systems that can compensate for different types of fading, the short-term frequency scaling factor of all types of fading is needed. Attention is focused on the short-term frequency scaling factor of clear-sky amplitude scintillation and amplitude scintillation (using the measurements of the 12.5/20/30GHz beacon signals) occurring with rain attenuation simultaneously, often referred to as wet amplitude scintillation. It is shown that these factors are strongly variable: they depend on various meteorological parameters and on the aperture illumination efficiency of the receiving antenna. In addition, it is shown that amplitude scintillation can only be compensated partly by means of ULPC, owing to the limited correlation of amplitude scintillation measured on two radiowaves with different carrier frequencies propagating along the same path simultaneously. Furthermore, a new procedure is presented to separate rain attenuation and amplitude scintillatio

Multiple-beam groundstation reflector antenna system : a prelimary study

A wide-scanning multiple-beam reflector antenna, two systems are investigated. A bifocal antenna, designed with the use of an existing method, appears to be unsuitable for wide-angle scanning. A dual-reflector offset torus-antenna showed promising results. As an illustration of its benefit, a possible application is examined: the simultaneous reception of signals from a number (n) of geostationary direct broadcast satellites with mutual distance of 6 degrees. Using this antenna yields advantage when compared, with respect to the total required reflector area, with n separate antennas.<br/

Millimeter-wave antenna with adjustable polarisation

A millimeter-wave antenna is presented that has an adjustable polarization. The polarization can be controlled by the input signal of the antenna and therefore no separate RF switch is needed. A completely planar feed network has been designed that employs branch-line couplers that allow to vary polarization depending on the input signal. The antenna has been realized and the concept of polarization diversity is demonstrated. Measurement results are in agreement with simulated results and validate the performance of the antenna

Application of the modal transmission-line method to radiowave propagation through building walls

The modal transmission-line (MTL) method is used to analyse the transmission coefficient of building walls, which is an important parameter for the accurate planning of microcellular mobile networks. For that, the buildings walls are modelled as multilayer periodic structures. After a description of the extended MTL theory, the newly developed MTL mcthod is applied to reinforced-concrete walls. From a comparison of the MTL results with previously published theoretical results obtained by the finite-element method, it is concluded that the MTL method is very well suited because it is accurate as well as computational-time efficient

Planar beam-forming array for broadband communication in the 60 GHz band

A planar beam-forming antenna array is proposed that operates in the 60 GHz frequency band. The array consists of 6 balanced-fed aperture-coupled patch antenna elements [2] that are placed in a circular configuration. The resulting array has a maximum gain of 14 dBi and a 3 dB scan range of plusmn50 degrees. To demonstrate the performance, test arrays have been implemented with accompanying feed networks that apply the appropriate phase distribution over the array for beam-forming at several specific scan angles. Measurements validate the proposed array configuration

Diagnostic analysis of radio propagation in UMTS networks using high-resolution angle-of-arrival measurements

This work describes high-resolution propagation measurements performed as a diagnostic survey in an operational UMTS network. The results were obtained using the measurement system previously presented in. Measurements were performed in a dense urban environment in Amsterdam, the Netherlands. Results showed that the measurement approach can be used to create a setup that is similar to the actual network scenario, and that is capable of accurately identifying the dominant propagation effects while moving through the environment. The results are especially important for mobile-system operators, because they revealed some of the causes of inadequate propagation prediction. This underlined the limitations of propagation-prediction models currently used by most mobile-system operators, and the importance of accurate propagation information to obtain the optimal network configuration

Application of the modal transmission-line method to radiowave propagation through building walls

The modal transmission-line (MTL) method is used to analyse the transmission coefficient of building walls, which is an important parameter for the accurate planning of microcellular mobile networks. For that, the buildings walls are modelled as multilayer periodic structures. After a description of the extended MTL theory, the newly developed MTL mcthod is applied to reinforced-concrete walls. From a comparison of the MTL results with previously published theoretical results obtained by the finite-element method, it is concluded that the MTL method is very well suited because it is accurate as well as computational-time efficient