Development of Planar Microwave Moisture Sensors for Hevea Rubber Latex and Oil Palm Fruits

Planar sensor for powder grain characterisation

“…Microwave sensors for dielectric material characterisations have been widely used for different types of applications [1], such as biological liquid and chemical tests [2,3], industrial materials [4][5][6], food and agricultural products [7][8][9][10][11][12] and medical applications [13].…”

“…The microstrip sensor projects emerged in the 1970s resulting in the first commercial sensor for fish meat processing [14]. Later, the same technique was used to measure the ripeness of the oil palm fruit [7] and the moisture content in green tea leaf.…”

Wireless Moisture Sensor Using a Microstrip Antenna

“…Water content, or moisture content, is often used to assess the quality of a product and its optimum handling and processing conditions. Microwave sensors emerged as effective tools for real-time, nondestructive, and continuous sensing of moisture content in a variety of materials [1][2][3][4]. The basic idea of the microwave moisture sensors is to measure the dielectric constant in a composite material such as the soil, foodstuffs, and building structures, which have permittivity that is mainly governed by the presence of liquid water [3,4].…”

“…Microwave sensors emerged as effective tools for real-time, nondestructive, and continuous sensing of moisture content in a variety of materials [1][2][3][4]. The basic idea of the microwave moisture sensors is to measure the dielectric constant in a composite material such as the soil, foodstuffs, and building structures, which have permittivity that is mainly governed by the presence of liquid water [3,4]. Some principles of the dielectric measurement have been proposed, for example, the time-domain reflectometry (TDR) [5], the microstrip resonator [6], and the phase shift detection of the transmission line [4] or parallel-plate electrode [7].…”