RF communications apparatus and manufacturing method therefor

A method of manufacturing a radio-frequency (RF) communications apparatus comprising:

• forming (140) conductive patterns (22) on a printed wiring board (82) to include a loop antenna (25) having a tuning capacitor (26) with first and second conductive pads (26′, 26″) juxtaposed on opposing sides of said printed wiring board and a conductive loop (56) having first and second portions (94, 99) respectively contacting said first and second conductive pads;
• measuring capacitance (230) of a feature (190) on said printed wiring board, said feature exhibiting a capacitance proportional to a capacitance exhibited by said tuning capacitor;
• selecting (234) a hole size in response to said measuring activity;
• and
• forming (236) a hole through said tuning capacitor, said hole exhibiting said hole size.

A radio-frequency (RF) communications apparatus (10) for use as an asset tag configured to be attached to a container (68) from which bulk product (66) is dispensed by tilting said container, said apparatus comprising:

• a planar dielectric substrate (92);
• an RF circuit (54) mounted on said planar dielectric substrate;
• a conductive loop (56) formed as a first conductive trace on said planar dielectric substrate, said conductive loop having a feed point (96) coupled to said RF circuit by a second conductive trace (97) on said planar dielectric substrate;
• a tuning capacitor (26) formed as first and second juxtaposed conductive pads (26′, 26″) located on opposing sides of said planar dielectric substrate, said first conductive pad being in contact with a first portion (94) of said conductive loop and said second conductive pad being in contact with a second portion (99) of said conductive loop so that said conductive loop and said tuning capacitor together form a loop antenna (25), said tuning capacitor having a hole (27), said hole having a size selected to tune said loop antenna;
• a tilt sensor (406);
• and
• a control circuit (402) coupled to said RF circuit and to said tilt sensor, said control circuit being configured to determine a duration for which said container is tilted, said duration describing a quantity of said bulk product dispensed from said container, and to cause data describing said duration to be transmitted through said RF circuit and said loop antenna.